Using Linux is rare among the general public, but very normal among the kind of person who may find themselves working at Cloudflare or at a potential cloudflare partner/customer.
I don't really buy the argument that they're pushing more captchas to you just because of using Firefox on Linux with an ad blocker.
It must depend on something else. Firefox & Linux have always worked fine for me, I cannot remember when I last got restricted by a Cloudflare captcha.
It's probably because I use Firefox on Linux with an ad blocker.
For my part, I've ensured we don't use Cloudflare at work.