How about VPN to create account? Then later on use Tor to log-in and make post? I did not try but it is my pop-up ideas. I think it can work and maybe better than Tor at beginning.
It's a good idea, maybe OP has to try VPN over Tor. Connecting into VPN first to cover the Tor exit node. Let's do that experiment with free VPN and change all credentials when login success.
https://www.makeuseof.com/tag/can-you-use-tor-and-vpn-together/It would be useless if OP uses free VPN, where it's IP likely already got big evil points. Besides, combining VPN and Tor is more complicated and could gone wrong easily.
Thinking about it, there is a big chance that the paid VPNs are abused too, but I won't buy one just to try.
Maybe not if you less popular paid VPN, but less popular usually means expensive, have bad reputation or had bad history.