On a more positive note, have you considered body weight exercises instead of the dumbbells which clearly don't inspire you?
Yeah, it's a good comment, thanks. The little bit of pure strength work I do is just some body weight stuff. I do have some limitations in leg work that is annoying. Squat type things, or even burpee type movements are a no-go for one knee (it's just about strain under flex, as opposed to unloaded flex (mostly) while running.)
There are so many forms of resistance exercise that you could do though that aren't dumbells.
AFM, my femur bone has healed, but my hip and knee are still fucked, so I'm still extremely limited, but doing a lot more than I was.
We got a Bowflex knock off that I'm calling the FauxBow, which I love. Ever since my body building days in my late teens I've always loved cable machines. Even back then I had bad knee problems and never did any squats or burpees.
The go-to exercises aren't the only options. I had to get creative at times, there were some exercises where my trainer had tied weights to me, or used resistance bands to isolate certain muscles, but it wasn't hard to work around injuries.
And that's only if you are looking to work muscles in a certain way. If you just want to exercise for general fitness and health, you could try something like Pilates, which is amazing for core strength, balance, posture, and stability, which is lacking in a lot of people especially as they age.
Even a lot of active people suffer from weak core muscles like psoas, especially if they sit a lot when they aren't active, and this leads to all sorts of problems from being active with weak core muscles, which is also very common as people age.
Back to me though,
I also got an exercise bike, but it's just for rehab purposes. I do 5 minutes a day with low resistance just as a range of motion exercise for the knee, which is really struggling with its new orientation and could need its own major surgery if rehab fails.
On rehab days I do a lot of leg-weight PT exercises, mostly focusing on the hip, glutes, psoas, and knee stabilizers.
My psoas is snapping, so it's one of my main priorities right now because it's snapping over a recently repaired labrum and it could just re-shred it, so that sucks.