Yeah all it takes is going for the right stats.
I would say the biggest issue is the lack of content. Specifically, you fight the same enemies, without really any end goal besides get to the next generic boss. That's probably the biggest weakness of the game, because even if you add a few more enemies, that itself doesn't really fix the game, it's just prolonging the inevitable.
It could use more to the gameplay. Not like making it a clicker game or anything, but adding different routes perhaps.
Having enemies look different would help a little, but it's still the same basic formula of basic attack and try not to get hit. Adding more active spells might help, such as freezing the opponent, mirage clones, getting attacked by muliple enemies at the same time, etc.
I know these fixes wouldn't really fix the main core issue of the game, but I'm not entirely sure your vision, so I don't know how to give the best advice for fixing the main problem of lacking content, besides just throwing in random filler (But that wouldn't really provide anything of value if it's just haphazrdly thrown in).
Going to more technical quirks, I noticed that the 5x multipliers also multiply other multipliers. So if I have 1 speed, and then 1 control after it, the control 5X the speed stat as well,
Also, even if anything reduces my magic stat, it doesn't matter because my damage somehow scales with the enemy, so it's better if I have 0 magic stat so I use only 1 stamina per hit.
I also want my stamina at base level, so if I die I don't take forever healing up.
But yeah, even end game progression, it's all about getting skills, but nothing really concrete for the character itself, besides the one keeping the skill slots.
Getting rid of the delay would help, but what would be better is if you could condense enemies, or at least waves, so you can progress faster instead of wasting so much time fighting canon fodder.