A lot of this applies to your situation.
Would add that you do glute bridges, to learn how to activate your glutes better.
Another exercise that I have had some of my clients do to strengthen their VMO and mimics a leg extension, but much more safe and productive.
Use a cable machine, set the cable about knee level, clip on a thigh strap, step you right foot thru it and pull it up to the back of the knee, step back, the cable will be trying to pull your knee forward, adjust weight accordingly, step back, pick up some dumbbells, and with you left foot, step back into a split squat position, squat straight down, knee should not go near the tips of your toes, but extend max about the middle of the foot, then stand up, pushing thru the bottom of your right foot and straighten the right knee completely, it should take some force to straighten your leg, so adjust the weight accordingly once you have gotten the hang of the movement.
Also, stand on a platform about 6" high to start, with your left foot to start, bring your foot slowly to the floor, touching only your ankle, and then take your foot back up by straightening your right leg, do a set of 12 for each leg 3 times, when it gets easier, either raise the platform or use weights/pack to get stronger, this exercise strengthens the muscles that get torched during steep and long descents, and which most regular exercises won't help with.