Former fitness junkie restarting

I'm a former runner/swimmer/lifter returning from injury. Okay, maybe more than injury. I spent a few years dealing with a degenerative hip that accelerated its decline this past year (plus a pandemic that closed all of the pools and saw none of the masters swim groups in my area restarted again after things reopened).

Anyway, I now have a new hip and have been cleared to *slowly* return back to normal activity. It's nice to be able to use my lower body again. For a while there, the only thing I could do was seated upperbody work (shoulders and arms).

So, what is a good program for me to follow? I need to re-strengthen and stretch out my left leg, restrengthen my core, and get my cardio capacity back up. Low impact please (I'm barred from running for at least a year, possibly the rest of my life, which kinda sucks).