for people asking about the 4 digit vs 3 digit lock... the painting room has TWO (at least) locked boxes. There is the safe which appears to be 4 digit, and the box which is on the same wall but closer to the door (still need to crouch) which is 3 digit. The 3 digit box has the dentist tool inside (from memory I think the code was 951, as is written on one of the paintings in the room). The dentist tool can be used on the 3 white vases in the living room (by the Time magazine) to get a key for the milf's bedroom, which you can use to enter in the morning.
Cheat engine works very well, both for money and for her passion level. They're just the default 4-byte values. Search for current value, then do a next scan every time you update it (earn money, spend money) until you only have one memory location left. Rinse repeat for the other variable (give gift, chat, etc).
Also, I was able to go into windowed mode (helpful when cheat engining and looking up tips...) by using the classic Alt+Enter hotkey
for people saying this doesn't need a guide/walkthrough, you're out of your goddamn mind lmao