Hello
I can't answer about steam. the game doesn't need to go through steam to be launched, you just have to click on Game.exe and it is autonomous.
for the same day that repeats, it's up to you. the game is a sandbox. the first ideas that Lolita gives are game aids, but, apart from going to class, nothing is mandatory.
In the CGroom, you can find tips to know what to do to unlock the CGs
I know about the rent bug (Lolita can't pay even though she has the money), but as it's to the player's advantage (CG easier to unlock) I haven't published a bugfix for the moment.
For the crash, you need the bugfix : https://pepette.itch.io/lolita-gone-wild/devlog/390277/bugfix-for-cg159b
don't forget to leave the house so that it applies to your save