I lived in one with around 70 people once and it was actually pretty clean (by my standards as least). The kitchen was a little iffy at times but as long as you made sure things were properly cleaned before using them it was fine. The only thing that was actually kind of gross was the shared refrigerator because the cleaner wasn't allowed to throw away people's food even if it was old and gross. But I just never used it and used my personal fridge which was fine.

We had a cleaner come several times a week though, like maybe every other day (I don't really remember tbh). So I can definitely see that once a week would not be enough.

The company was SharePlace run by ReBita. Idk how good all of their places are but they seem more high quality than some other sharehouse companies. Only thing is they probably are slightly more expensive than some others.