More so a mod from an Instance. But a community mod can still have impact if they are close with their instance admin, which can have an impact on visibility and reach in the Fediverse depending on how big the servers are. Fediverse isn't decentralized in the way most people think it is. In theory it is but in practical function it isn't. Every server is like a slick of the pie in the Fediverse, and servers with more users are bigger slices. These bigger servers have more authority and if they decide to ban you or silence your communities (and you don't retaliate by circumventing it with alt-accounts and/or lying on Registration to make them think you're someone else) you'll lose out on that chunk, and possibly 90% of the reach and interaction you'll get. For these servers it's a tradeoff because if they do it too much or too aggressively like Beehaw.org did they'll lose their authority (I remember when Beehaw people had huge FOMO blowouts about the Beehaw defederation of Lemmy.world and sh.itjust.works, now people don't even care, they killed the authority they had by killing their own reach), however when they haven't gotten to that state their actions can be devastating to the reach of individuals here. Someone starting their own server or community on another server in these situations won't really help because the pie slice of those instances is bigger.

Also even in the case of lowly moderators, if they moderate multiple large communities even without administrative abilities they can still squash your reach by banning you from the biggest communities. Similar to the issue of powermods on Reddit. Making your own communities doesn't help here because your reach will be limited since the people are still over there. And despite what people say getting people to go elsewhere is no trivial task, you basically need admin/divine intervention to even put a dent in Network effect.

If I remember, Lemmy is working on making sure comments and post history is exportable if you want to move instances. Having a backup of your account would definitely give even more power to the user IMO.

I do hope they do that, it wouldn't solve the issue of servers being big enough to have a noticeable impact on your reach but it would solve the issue of servers being able to axe your account and history from existence entirely. Unfortunately it doesn't seem like they really care that much about doing that, at least not moving post history. Currently it only supports moving subscriptions, description, Display name, and a few other traits which... I don't really see much benefit in. I didn't do it when I created an account here, since I knew that if lemmy.world banned me or was angry at me for making an account here (there was a short feude with dbzer0 at the time and they were banning people talking about moving here) it wouldn't really matter if I could take my subscriptions since 99% of them would be useless. Thankfully that didn't happen though.

I never wanted to claim that the fediverse is like nostr. I just don’t consider it to be authoritarian because of the first paragraph.

That's good, though unfortunately I know that there are some... Okay a lot, a worrying amount in fact who do. I don't think that Lemmy itself is authoritarian. I do think it is considerably better than mainstream social media sites like Reddit or Facebook, but I feel that telling people that admins and mods don't have any authority on lemmy and the fediverse as a whole is at best naive and at worse reckless and irresponsible, because they ultimately do have power and authority based on popularity and size. And it can have severe negative impacts that simply self-hosting or making your own community can't solve.

Of course this is also a feature of the Fediverse compared to Nostr because it means that shitty people are kept outside the fence (when they aren't lying or cheating their way inside) so it's a double edged sword. It's important people are aware of that, because actually one of the biggest things we do have against bad actors who are big + powerful and do this is awareness. Because if a big server is silencing people aggressively, action can be taken by other servers to limit their reach, and their authority is greatly diminished. Beehaw did it to themselves but I could see a situation in which another server might have it done to them because they are silencing criticism for objectionable views while promoting and endorsing those objectionable views themselves.

So in that sense, communities like !yepowertrippinbastards@lemmy.dbzer0.com or !modabuse@lemmy.sdf.org are really good since they help develop that awareness and can lead to action being taken to stop abuse, like removing of remote communities from instances, or defederation of hostile instances.