Greetings Oldtimer,
Many things have already been written on safe/joint friendly weight training, such as exercise selection and the importance of proper form.
I give you 3 things that work very well for me during times of injuries/pains (shoulders & hips in my case), and with 'very well' I mean that I was
(almost) able to train pain free and that the pain post-workout was much less.
1. Perform dynamic mobility work and stretches for at least 30 minutes once a week. Right after cardio is a good moment, as long as you're warmed up.
2. Train with resistance bands or combine them with free weights or machines. Esp pressing movements with bands put less stress on the joints.
3. Train in super slow fashion. The original super slow protocol is 4 reps with a 10 sec concentric & 10 sec eccentric movement, so that's a total T.U.T. of 80 seconds(!)
This works very well, but I found out that 3 reps with a 5 sec concentric/5 sec eccentric works more intense (i.e. more weight moved per second, while it's still not taxing too much on my joints)
I believe that the preferred volume/frequency is personal thing. Myself, I prefer a limited volume with a higher frequency (train a muscle 3 times per 2 weeks), but you also have those typical volume guys who want to pump blood into the muscle from all angles. What matters the most is that you take enough recovery time, which is mostly a matter of listening to the signals of your body.