What if you aren't willing or able to relocate, though?
I can't generalise to all the teams and companies, but this was my experience, and I've seen some similar profiles around me. I suppose if you really check all the wrong boxes, it may be hard to land an interview, but once you're in the process, you have a shot just like anybody else and it really boils down at how well you do at the leedcode questions. Concerning diversity, interviewers are trained to avoid common biases on gender, age, and recruiters have incentives to interview people from minorities. I would say that if you come from a minority, you are at an advantage and you're more likely to get an interview.
What is clear, is that not everybody graduated from top schools. There are plenty of SWEs coming from developing countries. Older people are more rare. I was hired at 45, and the bar was a bit higher as they wouldn't hire me below a certain level. I've also heard stories of people hired at 55.. so there's hope.
If you're unwilling to relocate, you may be able to remote work from a different country. This depends on the company and the role, and which country you want to remote from, but it's doable.
To me, the main issue with leetcode is that it's not transferable kills. It may be very frustrating to spend 100s of hours doing these problems and not being able to land a job in the end.
I definitely know a lot of Googlers and Xooglers who didn't graduate from top schools. Or at all.
Leetcode is the kind of thing I enjoy.
Many jobs are fully remotable now (tho it varies from almost all of them like Meta, to almost none of them like Apple). Sometimes slightly less money.