Cera has always been in a weird spot, where while too good at dealing with small groups of humans, it struggles a lot once the humans start to group up since, unlike carno, it has no tools to create an opening for its team without putting itself at immense risk.
So the aim of this suggestion is to give cera a way to help it do its job as a bruiser without making it too overwhelming to deal with for small groups of humans, while at the same time not making it too similar to carno:
Give cera an alt ability where it can't move nor attack but becomes completely invincible for a limited amount of time and decrease its hp back to 1300.
This may sound extreme but considering the raw amount of damage the human team can dish out in a matter of seconds it's also kinda necessary, plus it being a timed ability opens up more mind games and counterplay options than just increasing its health.
tl;dr: give cera armor lock and nerf its hp back to 1300