This is desperately needed. I want to use the /all front page for discovery, but it's lousy with porn and foreign language communities from the same few instances, upwards of 20%. I block on sight but it's like beheading a hydra. Having to entirely relocate instances or use a specific app to block instances is not a good solution.

It is an open issue at https://github.com/LemmyNet/lemmy/issues/2397 and it seems that the devs are willing to merge a fix but I don't know if anyone is working on it.

edit: in case it wasn't clear I am talking about the main lemmy code not this particular app. I don't know if this app has anything in particular it does.

On iOS the Memmy app has instance filtering. It seems like a custom filter, not something that is part of the Lemmy software.

I hope someone knows because I also don't care for the porn (you do you folks it's just not for me). I've been blocking the community as it comes up in the feed but there seem to be many.

Yes there is this option. Setting> post list >filter >instance

Probably the simplest way at the moment is to just make your own instance so you can pick who you federate with.