And then also give it to the classes that have a decent stats pool, insta toughness reffil mechanics, and other tanky things.
Sometimes restrictions is the option for balance. If weapons were asking for some sort specialization point it would be easier. Like if you take finesse weapons - you can’t have big HP/toughness pool but survives through evasion and mobility. But you can play Saltz zealot-Kerillian shade hybrid and it causes problems.
Either it should have been from the start for all humans to have their unique mark of the same weapon archetype, not 3 for every. Cause anyways in most cases there is a consensus on the best mark, it’s almost never all 3 are popular equaly.
Bolter is another example, if it were a separated profile for zealot like having incendiary bolts, there would be no problems dancing 2 years around how to make it not OP on vet and not unwieldy on zealot.
And then give bolter to psyker also, with psy active bolts
And also you could work on separated blessings pool more easy, knowing that blessings scales well with this class.