I used to have an account on the PB many years ago, but my credentials are no good anymore. I'd like to post some movie and TV show dumps somewhere, particularly that'll be indexed by Torrentio and searchable to debrid users, but I'm having trouble finding anywhere with open signups. I'm specifically uploading English media.
Based on that your choices are to apply for uploader status at 1337x, ThePirateBay, TorrentGalaxy (if it ever comes back up), or maybe Rutracker if you can deal with the English/Russian translation. Just getting an account at those sites may not be possible but you'll need to try that to achieve what you want. Not sure if they'll give you uploader status if you're just uploading the same movie/tv content they already have.
If you don't care about Stemio you could try uploading to BitSearch / SolidTorrents, those are DHT crawlers (same database I believe). The admin does allow people to add torrent hashes to the main database there.
Ah yes I think you're right, good catch. There isn't any distinction between a regular account vs uploader, they just use their skull system to denote "trusted" uploaders.