I don't what the max level for this game probably like 99, 100 or there maybe is no max Level. I can't really tell , i did not really level up on any of my saves behond level 26, because it did not really seem to make me a lot stronger behond that.
Also a that point i was already overpowered that i could one shot all none boss enemies.
Aside from that i defeated like literally almost all bosses in like 2-3 turn without seriously trying.
If i wanted to flex could even out heal all of the damage output of every boss in a one on one fight with the passive regeneration of the regrowth.
So i did not see any point in becoming stronger.