I got into the self-hosting send this year via my own website run on old recycled thinkpad on my own home connection. I a lot of time was spent learning about ufw, reverse proxies, header security hardening, fail2ban.
Despite all that I still had a problem with bots knocking on my ports spamming my logs. I tried some hackery getting fail2ban to read caddy logs but that didnt work for me. I nearly considered giving up and going with cloufdlare like half the internet does. But my stubbornness for open source self hosting and the recent cloud flare outages this year have encouraged trying alternatives.
Coinciding with that has been an increase in exposure to seeing this thing in the places I frequent like codeberg. This is Anubis, a proxy type firewall that forces the browser client to do a proof-of-work security check and some other nice clever things to stop bots from knocking. I got interested and started thinking about beefing up security.
I’m here to tell you to try it if you have a public facing site and want to break away from cloudflare It was VERY easy to install and configure with caddyfile on a debian distro with systemctl. In an hour its filtered multiple bots and so far it seems the knocks have slowed down.
Security issues are always a concern the question is how much. Looking at it they seem to at most be ways to circumvent the Anubis redirect system to get to your page using very specific exploits. These are marked as m low to moderate priority and I do not see anything that implies like system level access which is the big concern. Obviously do what you feel is best but IMO its not worth sweating about. Nice thing about open source projects is that anyone can look through and fix, if this gets more popular you can expect bug bounties and professional pen testing submissions.