If you can load the raw markdown, then you can copy and paste with the markdown link formatting.

I think the Reddit Enhancement Suite added a button to posts that would let you display the source. I can’t check that right now.

For Lemmy, open a post on the website and look for the paper icon. That will let you view the source

Trakt was popular in the past, and has integrations with Jellyfin, although some people may have left after their pricing/feature changes earlier this year.

Here is a relevant thread you might find helpful: https://lemmy.ca/post/38746526

Your account is marked as a bot, you can change that toggle in your account settings