These are the exams you’ll need to pass to teach. You’ll be able to “test out” of some but there will be several left to do.
https://gb.abrsm.org/en/our-exams/bowed-strings-exams/violin-exams/This is a decent explanation of the different qualifications needed for different things.
https://lcme.uwl.ac.uk/exams/strings-harp/violinI could have completed the U.K. teaching qualifications for dance in two years, but due to much more strenuous work pressure (day job), I wasn’t able to make it work. Then I had kids. But hopefully I’ll do them someday. I really miss being in the studio.
My professional friends (an anaesthesiologist and a dentist) are shocked that their professions honour foreign experience and qualifications, but that I can’t teach kids how to tap dance.
Id really consider either teaching in a school or playing professionally. Genuinely those will be the only viable routes for a visa. Especially now that the £2 million visa isn’t an option.
There will have to be a compromise somewhere. Either retiring and enjoying your time the way you want (outside the UK), or taking full time, intense employment for 5 years until you can qualify for indefinite leave to remain in the UK.
Hugs! Have you considered other countries that don’t have serious anti immigration policies?