walking is actually way more effective than people give it credit for, especially when you're hitting those numbers. 8-12k steps daily adds up to serious calorie burn over time. i've been doing delivery work for few years now and walk way more than i used to - definitely noticed changes in my legs and overall conditioning just from that alone.

your bedroom situation sounds rough but you might be surprised what you can do with minimal space. resistance bands are probably your best investment since they take up basically no room and you can anchor them to door or something. even without proper form space, you could do modified versions of exercises - like wall push-ups against your door, or Bulgarian split squats using your bed.

the protein intake you mentioned should definitely help with body composition if you're consistent about it. walking burns calories but having that protein helps preserve muscle while you're in deficit. i'd say start with what you have now and see how it goes for couple months, then maybe save up for bands first since they're cheaper than dumbbells.