Outer Quad (vastus lateralis) tear and recovery taking too long

2 years ago I tore this tendon after an mri I was told I had a 40% tear about 4-5 cm above the knee. The rubbish nhs scan was not very clear
I left it probably too long and there was dramatic muscle wastage on that right quad. For 18 months I have been doing everything I can to strengthen that quad and its incredibly slow going. I probably have been doing non optimal strength exercises.
There is a section of the outer quad (2-3cm) which simply isnt there any more I suspect I tore muscle away as well.

There are other issues in that 10 years ago I tore a small part of the central quad away from the knee cap and that bit of bone and quad is still floating around. I suspect the lateralis tear was caused/created/impacted by that bit of extra instability but that is my uneducated guess.

My question is ...

Can I hope to get full strength back to that quad with the right work or do I need surgury?

I am a life long runner and I am desperate to get back to running normally again. When I run now I am very left orientated and I am suffering all sorts of problems when I run. I have a garmin heart rate strap which measure left right ground contact time and I am 58% 42% which is really bad.

Interestingly when I sprint up hills or short fast efforts my run balance becomes mostly even and i dont feel the niggles that I get when I run at a steady pace.
I suspect it due to me running from the glute more when i sprint or run hard but when I plod I am much more quad orientated hence the imbalance...

Thanks in advance