You can use an app like voyager that lets you block specific subs. I have the porn ones blocked but you can just block all the meme subs that annoy you.
On the app I just hold down on the name of the sub and it lets me block it.
Some posts that are correctly tagged nsfw will lose that tag when federated across to other instances. The vast majority of nsfw posts do work though, which is making it hard for devs and admins to debug the issue.