[2021] Mods and Assets aren't downloading. Can't do anything to get it to work. Please help!

Definitely looks like your Steam isn't connecting properly. What usually does it for me is log out of Steam, shut it completely down, restart Steam and then log back in.

If that doesn't help either, I suggest reinstalling Steam, since you've pretty much done all the other steps that usually get it to behave.

https://support.steampowered.com/kb_article.php?ref=9609-OBMP-2526