Use Cap instead of hCAPTCHA (for the flagship instance)

GitHub stars aren't an accurate metric of popularity tbh. It's like Facebook likes back in the day, you can get a lot of them but only have 3 people know about your product. Judging by their site (https://trycap.dev/), Adguard (for their temp mail product), Bunny (EU CDN, see them as yuropean Cloudflare alternative) and Fraunhofer (German research organization) all use some form of Cap, be it heavily modified or not so there is/was some big companies reliance. I would bet it would be more but companies don't usually publicly endorse things out of their goodwill, they yoink and think later.