Filtering posts with keywords and hiding posts manually.
Certain topics cause unnecessary anxiety, on reddit they were easy to avoid with RES. Here the only way to remove a post from haunting you from your timeline is to block the poster, which is bit overkill.
User can specify keywords that are used to filter and exclude the users own subscription timeline from posts that include the words in the post-topic.
For example: User adds the keyword "died" in the settings to a filter list. The topic "Great actor of movie X has died" will now not appear in the feeds. There also could be a more advanced version of this that allows to assign keywords to different communities.
Hiding posts manually
In every post, the tools in the "three dot overflow"-menu should include an option for "Hide post", which makes that post disappear from the feed.