hmbrglr @hmbrglr
Impressive commitment to working out !

Not knowing if you are able to get advice from qualified PT - however,
if you can do squats, it is a compound exercize. I do mine
standing in front of a couch, which reassures me that, until I am much better,
I have a soft landing.
I'm sure I looked awkward and exceedingly out of shape when starting.
No matter.
It doesn't have to be deep squats. You will improve as you do
it more often. I read somewhere, it might have been Dr Stuart McGill,
that we all have different body mechanics, and some of us can do squats more
easily and squat lower than others.

Pushing out against a wall, or a countertop, to eventually, do push ups
on the floor: even on elbows at first.
I am not doing these on the floor, yet.

You are doing 5 lbs weights - are you doing overhead? Farmer's Walk, arm rows,
bicep curls.

Stairs, at home, or outdoors. It is a combination cardio and osteogenic.
There are different variations, when you get more fit, to use weights,
for example going up and down stairs.
With your scores, similar to mine, I don't know if rucking is recommended.
Or weighted vests.

Don't forget resistant bands. There are many videos on it.

As you say, you want to continue, to make sure your muscles don't get weaker.

Swimming and walking are wonderful, of course, however
I focus on doing exercizes to build bones and muscles.

Let us know what else you are doing with exercizes.