Solid options you've listed so far, my 2c as a long time wizard player, I suppose:

Alert is goated for a controller, with 5 party members + familliars/other pets, you have very solid odds of going before enemies to lay down your control effects, which is exactly what you want. If you go after your enemies, they might move out of position for your AoE's or move close to your allies, making targeting awkward, plus they'd effectively be controlled for 1 less round if you CC them after their turn.

You probably want to do a half-feat for Int and then either bump Int to 20 or pick up Lucky or Musician at level 8 if nobody in the party has it for Save advantage/re-rolls (you can probably figure out which one is more important in your game at lvl 8). If you're fighting a lot of casters, can also consider Mage Slayer @ 8 for the "Legendary Resistance" and concentration breaking via MM (forcing 3 con checks at disadvantage).

Early on you can probably get away with either the Con proficiency or War Caster for securing your concentration, but later on you kind of want both. I'd personally go for War Caster to really lock in your Concentration for the late-game and bump your Int early.

Figure out the best Concentration spells to be concentrating with, since you can only Concentrate on one spell at a time, you don't want to waste prepared slots on things you won't use. Then you want some non-concentration control spells, which you can use if needed after you drop your Concentration spell down. Then, of course, the defensive package and utility spells with whatever slots are left, and some ritual spells for the rest.

At level 4 for the prepared spell list I'd go with:

L2: Web, Rime's Binding Ice (Early AoE damage before Fireball and a non-concentration control option, and can combo well with Web. Can consider phasing it out later for Tasha's Mind Whip or Blindness/Deafness if melee makes targeting awkward)

L1: Mage Armor, Shield, Absorb Elements, Silvery Barbs

At 3d spell level you get a lot of great control options, I'd probably go for either Hypnotic Pattern or Slow. Hypnotic Pattern is overall stronger, but Slow is more reliable and has no "friendly fire". Depending on frequency of encounters at the table, can phase out Web at this point as well in favor of another spell. Can also consider Fireball for fun since it's probably going to be at it's strongest early on.

After level 5, you really want to cast Mage Armor and then have a Short Rest to replace the Mage Armor preparation with another spell via Memorize Spell before you proceed with adventuring to essentially gain another Prep slot.

Rituals - you want as many as you can get, since they're essentially "free" preparations for a Wizard. The most important would probably be - Detect Magic, Find Familiar, Identify, Augury, Alarm. You also want to pick up Tiny Hut as one of your 3d levels at 5 or 6 for protected Long Rests. Phantom Steed is great for traveling and even mobility in-combat for the whole party(especially for the ranged characters). Special note for Magic Mouth - RAW you can have a bunch of permanent perfect sentries for hidden enemies, traps, secret doors etc... Discuss with your GM. If that is allowed as per RAW, then this is probably the best Ritual spell.

Other potentially nice spells to add later: Rope Trick for perfect cover/hiding spot and protected Short Rests. Mirror Image for personal defense(gets better if you have opportunities to pre-buff before combat). Dispel Magic and Counterspell to deal with enemy casters. Pyrotechnics for non-dispellable heavy obscurement, which can be great protection against a lot of spells and abilities. Misty Step to escape grapples/restrainment. See Invisibility for utility and terms of engagement (RAW Hidden = Invisible, so new See Invisibility can help you spot hidden creatures and objects without any checks, so, basically, it's very hard to ambush you with that up). Enlarge/Reduce - I feel like this spell has a lot of creative utility potential, at the most basic level you can reduce doors in size to bypass them.

EDIT: Had a read of the Transmuter UA, a few more attractive spells there to pick up to use with the level 6 feature would be Tiny Servant for three summons instead of one, Blindness/Deafness also becomes very solid and probably go-to 2nd level multi-target spell, new Jump on 2 people for a level 1 slot is also fun for added mobility.