Cloudflare has been blocking "mainstream" browsers too, if you are generous enough to consider Firefox "mainstream." The "verify you are a human" sequence gets stuck in a perpetual never-ending loop where clicking the checkbox only refreshes the page and presents the same challenge. Certain websites (most notably archive.is) have been completely inaccessible for me for years for this reason.
Do you have something that blocks some amount of scripts? I need to allow third party scripts from either Google or Cloudflare to get a lot of the web to function.
