I'll save you some reading if you want.
If your elbow issues are golfer's elbow, follow this guide to a T. Basically reverse it if you have tennis elbow (reverse wrist curl instead of wrist curl, reverse the pronation exercise etc). Has fixed me (from pain lifting a wok/pan to +185 weighted chin up) in 8ish weeks multiple times:
ASK DR J – ISSUE 223 – DODGY ELBOWS REVISITED – Dr Julian Saunders
If you have patella tendinopathy, lucky for you as it is probably the easiest tendinopathy to treat. Slow full ROM squat/leg press/split squat (3 seconds down, 3 seconds up) 3x per week. Add weight and decrease reps each session (start with like 3 x 15). It will hurt like hell the first set, and get better each set. As long as any additional pain from the session dissipates before the next session you're fine. Once again, 6-8 weeks here and you'll be good to go.
If you have quad tendinopathy, it is a bit harder because irritated tendons have more blood vessels, and they get thicker. The quad tendon when irritated actually rubs against the patella (called compressive tendinopathy), making ROM trickier. I've had the best success with progressive ROM stuff here, with pin squats being my preferred tool. Start with like a 6 inch ROM if possible or larger if it doesn't hurt, and increase the ROM each session. 3x a week again. You need to go a bit heavier here from the start because the goal is increasing ROM over weight.
Also do some calf stuff.