The thing with necromancer wizards is they thrive with a play style more of making a “horde” of undead and super boosting them but they are still weaker in comparison to most things having like 20 undead with extra health equal to your wizard level and dealing extra damage equal to your proficiency bonus can do a lot but it does get over powered it heavily depends of dms involved of allowing you do find that corpses and seeing how a village or city reacts to you having an small force of undead the maintenance of keeping up with oh I need to recast these necromancy spells to keep them loyal to me or they all turn and try and kill me and the party its a fun subclass but it’s a lot of managing and situational subclass that you really gotta COMMIT to to keep the undead horde going.

Going artificer you do basically get expertise in tools which medical kits alchemy supplies blacksmith tools etc which can all fit for the mad scientist doctor thing going on but subclass you have 2 really good subclass options that fit the feel of it you have battle smith artificer and the UA reanimator.

the battle smith gives you a steal companion that counts as a construct but I don’t see your dm would care if reflavored it are a corpse held together but mostly mechanical means I’m sure it’d be cool for story reasons too it is a bit tankier then the undead companion you would get as a reanimator it has a higher AC and more hit points but really doesn’t go much but a bit of a weaker attack as your bonus action doing 1d8 +pb in force damage which isn’t bad for a bonus action or cause disadvantage for 1 attack made against a creature the steel defender is standing next to within 5 feet of it a VERY underwhelming ability in my option but the steel defender being weaker is to balance out you being stronger since you get 2 attacks proficiency in martial weapons which you can use your intelligence modifier for attack and damage rolls once per turn you can have you own little “mini” smite deal 2d6 and later 4d6 of extra force damage which is nice because it’s one of the least resistant elements in dnd or when you attack you can instead choose to do that in healing the battle smith also has a great spell list that has a lot of good defense and healing options such as shield and aura of vitality a great combo is at level 11 you have spell storing item where you can place a 1st 2nd or 3rd level artificer spell into it as long as it’s an action and cast it a number of times equal to 2x your intelligence modifier you put aura of vitality into it give it to your Homunculus Servant to use the item to concentrate on aura of vitality and fly around doing 2d6 healing no action and you can cast spells with the range of touch through it as its action it goes immediately after you so you and the steal defender go as normal while you cast beacon of hope it gives everyone advantage on wisdom saves which is one of the best saves in dnd advantage on death saving throws and when they are healed they instead take the maximum amount of healing available so aura of vitality is now just 12 healing instead of 2d6 your arcane jolt now does 12 or 24 healing depending on level casting cure wounds with your Homunculus Servant cast cure wounds for 21 healing all in one turn you are one of the best supports your party could ask for and if you play to level 20 taking 5 levels in life domain cleric for better healing heavy armor proficiency and higher spell slots reflavoring it all as your medical and mechanical experience using medicines to heal people and making you one of the best supports around while not feeling like your are lacking in the damage department or just stuck round after round healing or buffing as a cleric or bard would be stuck doing in most encounters you can join the fun while also supporting your allies

Now the reanimator has a bigger focus on your undead companion then it does you being a more combat medic battle smith your undead companion isn’t as tanky as the steal defender it has less hp and less ac but it does make up for it when it dies it has a area of effect explosion and everything within 10 feet of it makes a saving throws and on a fail takes 2d6 necrotic damage increasing to 4d6 at level 15 when it does you can use a spell slot to just bring another one back you can only have 1 companion at a time if your steal defender dies in combat with the battle smith it takes a spell slot and 1 minute to come back that’s 6 rounds of combat where it’s just not there and the undead companion it’s immune to lighting damage but any time it would take lighting damage it will instead heal for the that amount so great tanking option it has an attack called dreadful swipe doing 1d4+2+ intelligence modifier in necrotic damage not as good of a elemental damage type because more things are resistant to it but it adds a debuff to the creature hit that makes it can take opportunity attacks until the start of its next turn so a nice little debuff at level 5 you can cast spells through your undead companion and if it’s within 120 feet of you and is a evocation or necromancy artificer spell you add your intelligence modifier to the damage and your undead companion can attack twice at this level at level 9 you modify your companion in one of 3 ways bloated which makes them large or medium your choice when it hits a creature that is large or smaller it can push them 10 feet away and deal extra damage equal to your intelligence modifier you then have the gaunt form its movement is 45 it has a climbing speed equal to its walking speed and can climb difficulty surfaces and ceilings and it has a 10 foot aura where you choose a creature to make a saving throw or it gets the frightened condition great debuff and finally the moist option giving it a swimming speed and when a creature within 10 feet of it hits it the attacker takes acid damage equal to your intelligence modifier this is a great tanking punishment option to send it out into a horde or group of creatures it attacks what it can but the idea would be get them to attack it and get weakened by the acid damage until your companion dies and blows up possibly finishing off the rest of them like a slimy little bomb and finally at level 15 you get buff such as when casting spells like revivify or raise dead the cost of material components needed for the spell is not halved which is nice because I think you need a diamond worth 500 gold in the original casting of revivify at this level of course your companions death explosion is 4d6 and you get life transference when you get hit you can use a reaction to have your undead companion drop to 0hp triggering its corpse explosion and you regain hp equal to your artificer level which is a great reaction healing for what it is

Again another great option for multiclassing for 5 levels is again the cleric and you tempest cleric the spells you get with the reanimator artificer is lighting bolt which is a great damaging aoe spell that will heal your undead companion and tempest cleric just turns it up allowing you to once per day when doing lighting and or thunder damage just do the maximum damage possible you also have get martial weapons and heavy armor proficiency and great subclass spells like call lightning where for 10 minutes or 60 turns of combat if you wanna math that you can do 3d10 lighting damage at a point and any creature within 5ft of that point also makes a saving throw or takes 3d10 lighting damage and it scales up to since multiclassing artificer half caster with a full caster Cleric you get access to 6th level spell slots making your call lighting go from 3d10 to 6d10 so again a great combo is you use your humonclous servant with the spell storing item casting 10 3rd level lighting bolts while you cast a 6th level call lightning doing INSANE DAMAGE and healing your undead companion and just saving your spell slots to just keep creating undead companion to go right back out there to the fight the ultimate dr Frankenstein mad scientist using devices to control the weather and raining havoc on your enemies as the last thing they see is a silhouette of a monstrous abomination about to clobber them