u/Faizanm2003

Got the bike off marketplace. I was riding home and realized that the rear brakes were a bit off. Then would clamp properly but wouldn’t release completely, I assumed it was maybe the brake arms were too tight. I was biking uphill very fast and then suddenly my bike stopes moving. I look back and this is what happened to the derailleur. It’s slanted and stuck in between the tires

I already spent too much on the bike and now need to get this fixed with as little as possible. I’m not sure how to classify my parts, it’s a shimano 105 but not sure if I can just order any shimano part and install it. Will I also need to replace the back gears?

Is there a guide or any help I can use to figure this out ?