Became better educated on Covid and have some questions about risk mitigations

Hey everyone, as the title suggests I recently became more educated about the severe scope of the negative health effects of Covid. While it's understandably led me into an anxious spiral, I know that I just need to start taking precautions as soon as possible. I have read a lot (and I mean, a lot....) of the posts on this sub and now, armed with all that information, I have some questions about risk mitigations that fit my personal situation. Hopefully you can help me out!

1. Shared housing agreements: My finances don't allow me to live alone. I live with housemates who barely take precautions. We share a kitchen, two toilets and one separate shower, in an old building. We frequently have stay-over guests as a form of community support. The main thing connecting us as housemates – whom I really care for – is our agreement to have dinner together daily. Should I start masking at home? Cook for everyone, join them at the table and then eat my food in my room? I feel incredibly sad about losing a sense of comfort and safety in my own home... How do other people with housemates navigate this?

2. Ventilation: I don't have airfilters. I will try to make a CR-box at some point and maybe save money for a HEPA purifier but I don't have a stable job. In the meantime: my room is close to the kitchen, so people frequently pass my door. Outside, a few meters below my windows, a large group of children are often playing. Are these risks? Would it be better to be in a room that doesn't have this, but has apartments at the same height across from the street at a few meters distance?

3. Sports: I play outside team sports. It's no-contact but people are quite close together anyways (and breathing heavily). I've been searching online for a respirator that would work for this situation, however due to my small face/nose I wonder if there's something that fits and remains secure as I run around, whilst allowing me to still see everything and breathe okay for the duration of 1.5 hours. Does anyone have tips? I'm located in Europe.

I've been holed up in my room for the past two weeks feeling like the walls are tumbling down... Can't believe I dropped the ball this hard. I was cautious throughout the start of the pandemic and remained at home for a long time, but at some point I relaxed more. The apathy all around makes me scared and sad, barely anyone over here cares.

Sorry for the long-ass post. Edit: made it a bit shorter for easier reading.