> I get unsolvable recaptchas all the time, especially on cloudflare pages

Repeated problems with cf and similar like this seem to be more common for users behind CGNAT (most mobile users for example). Presumably all the other hosts sharing the same final outgoing address(es), some of which will be running bots either deliberately or because they've been infiltrated by malware, confuse the heuristics that decide how often checks should be made.