My bad I forgot other suggestions I had.
Firstly I agree with the comments before me saying there should be more kissing options with Anna, especially earlier in the game as her relationship with MC is progressing. These scenes could even go through a progression, for example early in the game MC kisses her on the cheek, then later on the lips, then later fully making out in the love route and perhaps swirling tongues open mouthed in the slut route. I also think it would be good if in some of these kissing CGs the MC is at least partially visible. If Josef does not know the truth and hasn't left, MC and Anna should be able to sneakily make out or grope each other during movie night while Josef is focused on the TV, and if Anna is on the slut route she could reach into MCs pants. The dialogue option to get that scene could be "Whatever you want to watch, Josef" when they ask MC what to watch.
Secondly it would be good if there was an option to have more scenes with Anna in MC's bedroom. For example MC could ask Anna in the kitchen or in the hall if she has time to meet him in his room, then depending on how many hearts Anna has there could be more options including groping, kissing, blowjobs and sex. There could be a random chance that Adrian or Josef knocks on the door, with their dialogue depending on if their sharing routes are active or if Josef knows the truth.
Leading on from that, If Anna is on the slut route and MC reveals the truth to Josef and Josef stays but does not start the sharing route, i.e. selecting the "I'll take good care of mom" dialogue option, then there should be more scenes involving cuckolding Josef. For example, MC and Anna should have a scene during the movie night whereby they either make out, have sex, or she gives him a blowjob, all with Josef in the room trying to focus on the TV and he could complain that he can't hear the TV and ask them to go somewhere else. They should be able to invite Josef to the basement to do a cuckolding scene. Anna should still give MC the bedroom key and her dialogue in the bedroom scene could mention getting her pregnant on Josef's side of the bed and staining the sheets. When Josef knocks on the MC's door on Wednesday morning MC should still be able to answer "I'm with mom, go away". There could be a scene in Josef's office where Anna rides MC in the office chair and afterwards Josef could complain about having to clean stains from his chair. MC should still be able to have Anna to himself on both the Anniversary and Valentine's day if Josef is being cuckolded. When having sex with Anna in a location other than the apartment, there should be an option for her to video call Josef.
That last part also has given me the idea that if Anna is in the slut route and Josef doesn't know the truth, then Anna should be able to answer a phone call from Josef but she attempts to hide that she is having sex.
If Anna is in the slut route and also the Adrian sharing route, then when Josef asks for extra cream in the coffee there should be an option for Anna to make both MC and Adrian ejaculate into the coffee. Also it would be good to increase the frequency of the "Extra Cream" scene a little. Not too much but I feel like I have to visit the kitchen 50 times to see it.
I almost forgot my most important suggestion of all! It should be possible for MC to impregnate Anna even if Josef stays and isn't sharing / doesn't know the truth. This could be one of the scenes that plays in MC's bedroom if you don't want MC to have the master bedroom key. Or it could take place in the master bedroom but only on Fridays when Josef is outside.
Also it would be good to have different ending scenes for sharing with Adrian, and also for Josef knowing but not sharing
Ok I think I'm done lol Keep up the good work!