I don't think that's the case, every time I improved a character I noticed that change in the game.

There is a level limit for each character, I don't remember what it was because I played it a long time ago, and I had reached the maximum level with each girl, at that point I continued to gain experience points but the game no longer gave me points to distribute in my stats.

Max level is 200 of each character and the attack speed limit is different from girl to girl and most of your stats are much more better with your gear. The limits from the stats are 100 attack, 50 attack speed, 51 crit, 50 supa crit, 100 hp and 100 def. I don't know why the limit from crit is 51. The delay you mean is a bug i think where the girl don't make damage till she get hit from an enemy. Sorry for my english. It's not my main language.