I would focus on upper body, core, and leg exercises that don't require bearing weight on your feet.

If you belong to a gym, ask a trainer what weight machines you can use (the answer will probably be most of them - the challenge might be getting from machine to machine )

Core exercises like basic crunches, leg lifts, oblique work with medicine balls etc. all comes to mind. Pilates-esque mat work that works multiple parts of your body. I'm getting my butt kicked by a personal trainer 3x a week while avoiding anything that strains y knees, so it's possible! Good luck!

i've had several surgeries that have required no weight bearing for weeks or months. honestly, i think a lot it just needs to wait until you can get back to weight bearing. focus on your physical therapy exercises in the meantime. if you are using crutches, a walk can be a good workout on those things!

sit on a balance ball while boxing.
use handweights while sitting or lying down.

I have a foot injury. No weight bearing for a month, no swimming, no stationary bike or cardio. What would you do? Thanks for any tips.