Filter subs from r/all.
Without having tried it, I would guess that it only works for the old reddit layout (old.reddit.com). This seems to be the case with similar scripts, like: https://www.reddit.com/r/GreaseMonkey/comments/70sw81/script_that_hides_subreddits_from_rall_compatible/ and https://greasyfork.org/en/scripts/32226-reddit-user-subreddit-domain-filter
Myself, I might try the "RES" addon, as suggested here: https://www.techjunkie.com/block-specific-subreddits/
Doesn't work in Edge
My filtered subs are still appearing.