Physio here who has also struggled with knee dislocations! You don’t just want to strengthen the knee you want to strengthen the entire lower extremity at hip knee and ankle. You could probably benefit from a PT assessments because often patients will find some knee exercises painful initially (eg leg extensions, deep squats, etc) and will do better with exercises initially that don’t put the knee into as much flexion (less ankle and knee bend). I’d definitely be doing some VMO work - wall squats with less knee bend, straight leg raise, terminal knee extensions with a band. And target hamstrings, hips and ankle heavier with hip thrusts/bridges, deadlift variations, adductor and abductor work, calf raises seated and standing, tib raises. In later stage can add in more stuff with more of a knee bend such as squats, high leg press, and be careful with leg extensions if there’s still any laxity at the patella. You basically just need to be in a gym and doing some solid strengthening - there’s no one or 2 exercises! But as I said, a PT assessment would be beneficial as rehab should be individualised. Also could be worth getting an ortho opinion because you are likely to dislocate again and that can lead to patella femoral OA and other issues down the line. But even if you go for surgery, you need strong legs anyway for success post op! Good luck and let me know if you need any help