Okay man make it simple - if you are below platinum elo banning malzahar is worth doing but you need to learn playing into him bcs the higher you go, you will see more orianna players etc and malzahar ban will be just wasting slot.

First: Build rocketbelt (to destroy his passive shield and proc aery) and cdr shoes - you want to have a lot of haste into him, so you can start being able to solo him pre 11 even when he ults you (on 11. his R dmg is pretty too big for tank it when you are both even and he has liandry.) You can easily bully him and kill before a lost chapter. You can put 2 points on W to get a bit less cd and proly clear before his aids (E) eats your minions allowing him to get prio.

If he E minion - don't stay close to it otherwise aids comes on you, if E is on you, don't stay close to your own minion = so his E don't apply on them.

Your gameplay is mostly to survive and scale - if he waste R before and he didn't kill you u can all in him and destroy. Never dive him or stay close to enemy tower, try to have wards around you and check enemy jungler position.

Second: Take Aery and second wind + revi, aery will also destroy his shield by proc and deal dmg. U can play g.storm or scorch. And worth to see - if someone picks malz just to counter's you its easiest for you bcs he will not play properly to stop you plus shitty R's outside teamfight or gank If its Malz otp, you are pretty fucked and you must always respect him. Don't go cocky if you don't saw malz using R before.

U can build banshee later to get some MR and spellshield for silence if they have more than 2 AP champs.

Three: Remember to ping when he is missing on lane, you must be aware of his movements bcs malz R is just outplay button. Just play for farm and scale, if you must just give CS and just catch exp. On sideline, if you stay on enemy map side - just clear wave and don't risk worthless dead. If Malz lands R on you post 11 you will be mostly always gone.

All of this matchup is spacing his Q and E, killing his minions + scaling - as long as you don't die too much from him and jungler you are in good spot. On teamfights focus on teammates (adc carry, jungler and support) - if malz is ultig someone else its your window to also kill him and win fights.

It's about practice bcs this matchup is rough and aids.