In Jebora, you can try to block a community via a post by pressing 3 dots icon then click "block [community name]". I think you even can block the community without open the post in the home page
In web ui i think there is no way to do that yet
Also check your nsfw settings by unchecking "show nsfw content"
If that's not what you wanted, I suggest you open a feature request in Lemmy's repository or lemmy-ui's repository
Edit: fix formatting