Apps can fill that gap to some degree now, but we need widespread adoption of tagging before it's very useful for this. I'm not sure lemmy itself will ever support that tbh. Reddit never had it, and there's a laundry list of issues already on the official tracker.

Maybe everyone that moderates a community that sees this could strongly consider the important tags being implemented at that level, if the C/ contains things that are difficult to filter via blocking.

As an example, there's no need for a C/ that's dedicated to knitting to mandate a political of nsfanything tag when that's not going to be part of the C/ to begin with. Not worth their time. Something a bit more generalized, like a meme C/ would be nice if they added politics tag for posts of that nature, maybe one for sexual (but not porn) subject matter, but wouldn't need an nsfl because that's not going to be allowed to begin with.

The app I use most, Connect, has filter function, but it's only as good as other users make their titles.

There's no such thing as a perfect filter though. Doesn't matter how it's implemented, there's always gaps.