If it's purely bot traffic, then Anubis could help

You could have seen it on some websites already

https://anubis.techaro.lol/

Just to add to the two negative replies, I find Anubis to be the only system that doesn't ever get in the way. My browsers have Javascript enabled and, so far, it never took more than a fraction of a second to complete the checks

Every other system I've run into has constant false positives, e.g. Google captchas will sometimes say I've failed and make me do the hardest level (if it wasn't giving me that already), Cloudflare regularly thinks I'm a bot, Codeberg blocked me before, Github signup captchas used to take ~15 minutes to complete and then still said "well you failed, try again", Github's general rate limiting has false positives (some days I browse a lot, other days little, and on the little days it'll sometimes go "slow down" with no recourse whatsoever, you're just blocked for an indeterminate amount of time), OpenStreetMap blocks my browser at work because I'm using Firefox ESR instead of latest stable and it finds that user agent string to be implausible, whatever the german railway operator uses since a few days is triggering on me constantly, etc.,

etc.,

etc. Constant blocks everywhere.

With Anubis, my understanding is that you do the proof of work (with whatever implementation you like, it doesn't have to be the Javascript one that they provide) and you can move on without ever doing any task yourself. The power consumption is a shame, but so long as attackers aren't even doing this much, the couple Joules it takes doesn't seem to be an issue

Of course, the attackers will evolve, but for now...

anubis only works against lazy scrapers, and at a cost to your users. I'd prefer people not use it.

Bot traffic comes from machines that usually have a lot of idle cpu (since they're largely blocked on network IO as they scrape a bunch of sites in parallel), so they can trivially solve the anubis "proof of work" challenge, save the cookie, and then not solve it again for that site.

The only reason scrapers don't solve it is if the developers were too lazy to implement it... and modern scrapers also do, codeberg stopped using anubis because modern scrapers were updated to solve it.

The "proof of work" has to be easy or else people on old cell phones couldn't access your site (since an old android phone would start to overheat and throttle trying to solve a challenge that would take a modern server even several seconds), and it also consumes your cell-phone user's batteries, which is a really precious resource for them compared to the idle cpu on a server.

Please no. I'm a non-bot who gets stopped and turned away all the time by that menace. Anubis doesn't work without JS.

One of the things I give duckduckgo a lot of credit for is that while they're quick to interrupt me for a bot check (sometimes multiple times in a span of minutes) they'll let me identify ducks even on the most locked down browsers I use.