It’s a concern even with a reverse proxy. The reverse proxy encrypts your connection from A to B, but does nothing to stop the various security concerns that have been noted. Because those concerns don’t rely on intercepting unencrypted traffic. If you can reach Jellyfin’s main log in page, you can exploit it. Full stop.

The only way a reverse proxy would stop someone from being able to exploit it is to include a separate login on your reverse proxy, meaning attackers wouldn’t even be able to hit Jellyfin’s landing page unless they know your proxy’s password. But notably, this breaks basically everything except for browsers. All of your smart TVs, mobile apps, etc would stop functioning, because they’d bounce off of that reverse proxy login page.