I don't have any injuries/pain, but I do have some noticeable imbalances between my right/and left sides and a general lack of posterior chain firing, so instead of jumping into strength training this year, I decided to start with some foundation work. After some search I settled on the program from SoCalBikePT. I'm only two weeks in, but it really focuses on the basics and getting muscle coordination/firing patterns. Anecdotally, I've already seen a noticeable (R/L pedal balance measures) shift in my ability to get more glute/ham in my pedaling and apply more constant pressure with my left leg.
Also, nothing in your body works in isolation, so look above and below your knee as well. I have notices that I shrug my left shoulder to compensate for not driving through that leg, so the work on my scapular retraction and lat mobility helps release the hip a bit and drive a bit more through the left side. It can be a bit of a rabbit hole, which is why I chose to get a program. Otherwise, I'd be trying to fix everything at once and not really creating any knid of real progression.