Need to do single leg exercises in the gym to get that leg and hip up to par. Work both sides but do single leg exercises w/the weaker leg determining the weight and reps. E.g., lunges, Bulgarian split-squat, single leg Romanian deadlift, etc…
As for the saddle change and pain possibly related to it, I’d see a fitter and have your fit checked. Maybe your shims are inadequate or incorrect? If not the leg length, then it’s possible that when that weak leg gets fatigued, your form breaks down resulting in you compensating elsewhere and thus getting pain where you shouldn’t get pain.
How are you doing? sounds a lot worse than my accident! Hopefully your back cycling now. I didn’t get an operation they left me to heal naturally. Just this week I’ve started weigh bearing and I’m allowed on the turbo just not sure how much. Planning on 10 minutes just turning the pedals.
I started riding on march 15 2023 on the real road bike, about 1 year exactly since the accident. And rode Haute Route Alps 2023 in late August 2023.
I was on Zwift earlier than that - 14 May 2022, I did 15 minutes very slowly at that point and with 100w average power.
I would go by what your doctors say is okay and also what the CT scans are telling them about bone healing. If you don’t then it will set back your healing. Weight bearing for you at the moment is probably just minimum weight bearing, and not riding on Zwift at the moment
These days I ride okay, but I’m with one leg shorter and smaller than the other and my power balance is 45/55. You may find you end up with a similar power difference which is hard to change.
I use a lot of shims on my left shoe to address the shorter left leg. I’m using even more shims than what Shimano gives you normally and I’m using different screws to fix the cleats in place. This has helped a lot.
Something else the doctors will probably have you do is stretches. The physio will guide you on that and its important for getting back your range of movement in the leg. This range of movement is restricted for me regardless and I’m stuck with that.