'Other' storage in macOS Big Sur

Hey, I was wondering why I have 176,2 GB of 'other' storage on my Mac. I don't think it was this big in Catalina or any of the other updates. I have no idea what might have changed. Is there a way to delete some of this stuff? I already tried a few apps like CleanMyMac X (which works really good btw). I just started using Boot Camp and realised 500 GB might not be enough. I got the SSD outside of my old Mac and (with an adapter) plugged it into my 'new' Mac. Then I put a lot of movies and stuff I don't really need onto the old SSD. My Boot Camp partition is now a little bit too small, but I would still like to have at least 100 GB of free space on my Mac partition, so I can still do whatever I want. I already transferred most of my files (as you can see below), but I have no idea how I can delete some of the 'other' space.