It would be nice if we could reset heroes and upgrade them the right way to get maximum power.
What do you mean as the right way? There is only one way to upgrade a hero: increase everything to make it stronger.
If you mean so that resources could be distributed to other heroes, that would probably break the game everyone would be able to instantly power up any new hero by simply resetting some older, obsolete ones.
You’re right, this game wasn’t designed in a way where you could take materials back after using them. You’d be very lucky to see any game do that & I can’t name any.