Well, I certainly have the ability to pass hard interviews with a lot of preparation, but there comes a point where you wonder if it's at all worth the effort.

I had to cram for a FAANG interview earlier this year after being unexpected invited to apply. I came close but didn't get the job and was told I can try again in 6 months. BTW, I'm in Los Angeles.

Then the past few months I've had several other big tech companies reach out and told them I'm not going to interview this summer.

I recently had a former Microsoft Program Manager tell me that "the more experienced the person being interviewed the worse they are at interviews because that haven't used that part the brain in 20 years".

The interviews are such a pain now make me kind of wish I was doing something other than Computer Science.

That I definitely agree with but if I understand you correctly you're quite miserable now so an alternative looks relatively attractive.

Can you try to get into the hiring committee at your current employer? You'll get some free practice.

Above average in which group though? If it's a competitive field where only the people with relevant PhDs get called back in for an interview, then you need to be at the top end of that group to get a job. Being above average in some broader population doesn't really mean much.

(I don't know OP personally and I'm not commenting on them specifically, they could be amazing)

In my (limited) experience there is definitely a bonus for being the very best but I also believe the London Quant job market is big enough to get a decent quant job without being IMO material.

You have summed it up exactly. The salary and talent pool have bi-modal distributions.