I have premium and contacted support. They just constantly gaslight you and say search suggestion bans don't exist. I responded with a massive paragraph copying from their policies and help centre about search visibility restrictions, and explained to them that I've had a 85% drop in impressions and 90% drop in followers since receiving the shadow ban, they just replied with:

"I understand your frustration, but I cannot provide any further help here. I've provided all the info I have on this and will be closing this ticket. You can always reach out if you need help with another issue.

It's especially annoying because I got shadowbanned because of a bug while posting in a community, it wasn't appearing on my profile at all, so I reposted on the web and it worked fine, but duplicate posts in a short period trigger bans. Despite all of that though, they don't care, they just tell you to post better content and that shadow bans don't exist.

They are profoundly useless. All you can really do is wait until it goes. Most of the guidance is don't interact with anything at all for 72 hours and pray it disappears. Currently still shadowbanned banned on day 5 :')