One cool thing I've discovered is that at least inside apps, those links with !!!exclamation marks to other subreddits work within the app and within your instance. So that's cool. Not sure if it works with comments, since they're a different structure.

I'll test with this comment from a german instance: https://feddit.de/comment/747555

And the same comment from within my instance: https://lemmy.world/comment/779107

So the second link works but first doesn't, its misread and goes to some other post.