You are not the only one. In general, if someone abused some IP, before you got it, then you can see the consequences. It is a sad thing, that many Tor nodes are misused, and they are then blacklisted, or temporarily-banned. In general, there is only one working solution, if you are in a hurry: try a different IP. But obviously, it only delays the problem, without solving it. And I don't know the solution.

However, if the abuser will switch to a different IP, and the lock from Cloudflare has a timeout, then it should be possible to use the same IP again. I guess many locks are temporary, because in other case, it would be impossible to access clearnet from Tor.

Well, there are other solutions. But I wonder, if there will be enough users, willing to switch to P2P-based forum. Because then, DDoS-protection would work as in Bitcoin: if you have many nodes, with proper setup, then you cannot DDoS some P2P network that easily. However, will people agree to run their own full nodes, and download all posts, no matter if they are going to read them or not? I don't think so, and that's one of the reasons, why we have so many centralized points on the Internet: not every user will agree to share its own resources, and set up a full node.

By the way: I posted this message from Tor, so it works for me. However, I encountered similar problems in the past.