If you don’t mind self hosting, I’ve used Gitea. There are no limits if you self host. I’ve also heard good things about self hosted Gitlab. If your looking for something remotely hosted like GitHub, though, I’m afraid I don’t know of any free services I would trust.
Well, first thing, you should read “allow list” as “federate ONLY with these instances”. Block list is the opposite of that, “DO NOT federate with this instance “.
Try removing everything from your allow and block lists and see what happens.