sarms for a very tall lifter

I’m very tall, over 6’8’’ .. long limbs and always had knee and elbow issues
briefly was able to dunk, but upon landing twisted up my knee so I don’t even jump anymore.
Any advice when it comes to sarms and which ones are good for joints?
I read that ostarine and nutrobal were good, but I’m not a weight lifter. How would I dose them?
I’m 50 years old btw