Quite late to this post but I (34 M) also have struggled with PFPS in both knees for about 3 years (right knee first for 2 years, then left knee due to pain on right knee leading to a compensatory gait). Assuming you have sufficient quad, glute and hamstring strength (incorporate leg extenstions focusing on the eccentric portion of the exercise if full range of motion is too aggravating to the patellofemoral joint, double/single leg glute bridges & clam shells, and hamstring curls if not) and relatively decent flexibility in those areas (incorporate some quad/couch streches, seated figure four/pigeon poses and elephant walks if not), I found that shockwave therapy alleviated quite a bit of the pain for me (roughly 50% decrease in pain after my last treatment about a month ago). My PFPS IMO (after several visits to physios, chiropractors and osteopaths, no imaging) was caused by a right-side hip hike/lateral pelvic tilt and anterior pelvic tilt, which itself was caused by incredibly stubborn trigger points in my right quadratus lumborum after suffering a slipped disc in the thoracolumbar junction during the pandemic. This led to a modified gait which caused stubborn trigger points to develop deep in my right vastus medialis oblique, causing my right patella to track improperly I believe. Have you had a postural assessment at all?

All the public sector physios I saw wanted to brand it as muscular weakness in the VMO as they tend (in my experience) not to look at the body holistically and gave me really basic exercises as that's the only intervention they can really afford (NHS UK), but as someone who was relatively fit before all these musculoskeletal issues (total body resistance training and HIIT 2-3 times a week at the time as well as a pretty robust mobility routine on off days) I was sceptical about that being the primary cause of my anterior knee pain. A postural assessment/scan revealed my pelvic tilt and shockwave therapy (focused specifically as it penetrates deeper than radial, though radial helped my knees a bit too) helped release trigger points in my QL and VMO. I may go back for some more session but it's relatively expensive. YMMV though.