That’s a bummer. I’ve had the hamstring tendonitis and agree that it is no joke! And yes, too high of a saddle can aggravate this. And yes, I can see where too low will make patellar tendonitis aggravated. Could you settle on an in between saddle position? Or another thought is leave the saddle low and try shifting it back some on the rails to take the majority of the bend out of your knee at the bottom of the pedal stroke. It may work or it might not but it is worth the try. For me it helps a little and seems to favor better climbing and recruitment of the quads in my “wheelhouse”.

When I had the bad tendonitis, I hate to say it but I brought it on myself from making a “flight into fitness” - basically what I mean is that I was out of shape and then jumped whole hog into big mileage without enough gradual increase in miles or rest days in between. Also, - in addition to your PT exercises, what type of stretching regimen are you doing? If you have access to weekly yoga classes (2 or 3 times a week is what I strive for), these are super beneficial for developing flexibility and stength through an increased range of motion.

For the patellar tendonitis I would ask - how are the quad sets going? Can you advance the level of difficulty of your quad sets by using light, then moderate ankle weights? In my experience, patellar tendonitis is completely curable through consistent application of the PT exercises that strengthen the quads and therefore align and draw up the patellar tendons.

I do get sore in my hansgrings but never to the “tendonitis” stage anymore thanks to the methods to ameliorate the condition as outlined above.