what if you could infinitely spend/recover juice at the juice fountain to change your stats? similar to how you can enlarge/shrink weapons, sure there's "no maximum amount" but with the juice cost going up as you increase you may not want to go to infinity
however once you get to a "ugh everything costs too much so there's no point to any upgrades anymore" level, it'll run into the same issues as the current stats with there being not much to do late game
it's not flawless and honestly you're "level as you play" approach seems more fun, im just giving my little bit of feedback to my tired brain can come up with, hope it makes sense and i hope when you make the stat update you can be proud of it, because i sure will be!