>>138866
I'd focus on getting main dpses up to speed as the top priority, with double crit on every echo and lvl 10 skills on their biggest sources of damage, you should ask here which ones to level up first though, Prydwen straight up has wrong information regarding this
Healers are pretty irrelevant stat wise, at most only energy regen matters for them at all, all of the buffs in this game come from outros or echo sets or echoes themselves, and none of those scale off of any level or exp requirements or anything like that
I 30/30'ed past ToA with a lvl 50 cantarella and shokie with main dps Changli for exemple, because the buffs simply didn't scale off of level, and the main dps is hogging the vast majority of field time, quickswapping also allows you to maximize that field time even when building concerto with support characters.
When it comes to ToA you can have your best team tackle the middle tower, solo the lower floors with fairly unbuilt DPSes, and take on floor 4 or left and middle towers with one or two characters that are well built. This really just makes building dpses the more important step, but sub-dpses like Cantarella (who can also be a main dps if you just use her with Sanhua) also provide good damage when built and they should be built eventually too, Verina and Shokie barely matter at all which levels they have, Shokie wants 250ER which is simple enough with 3 cost echoes and a ER weapon, aside from that it's irrelevant what their stats are or what skill levels they have