Lots of misconceptions out there about blocking and fediblock and so forth.
Not that I am an ActivityPub expert, I am not, but I have been in the game on other levels for quite a while...
and I remind folks that yes you can block an account and you can block a domain even if they never sent you a mean reply/DM...
hit a few volatile hashtags and you will see who the bad actors are. Click around and you will find the option to block them, up front, before they even know that your account exists.
Also, if you know anybody who needs a very straightforward explanation of how to block domains en masse, you can find it here: https://wolfgangsdogassistedhuman.substack.com/p/youre-not-at-the-mercy-of-mods-and
Seems like the sort of thing people following #Mastodon #MastodonSafetyTools #TwitterMigration #MastodonServer and #Moderation would find useful.