Sometimes I've noticed that a seller will repurpose the product page for a previously seemingly legitimate product with good reviews to sell something entirely unrelated while benefiting from the positive reviews of the prior product.

Depending on the situation, up to #13 for me. A caveat to that might be whether or not the creator has appropriately priced their product so as to justly compensate themselves without charging consumers excessively. While I had it in my Steam library already, Factorio deserves to be pirated for breaking with the standard practice of not raising game prices with inflation. Same with Sega's anti-consumer move to remove the Sonic ROMs from the Sega Genesis collection to boost sales of Sonic Origins.

Gotta try to drag a few good people back from Tartarus...

I think HDEncode and ReleaseBB are among the best DDL websites, though there's other options listed on the FMHY and Megathread lists. To make practical use of them though, you either need an expensive Rapidgator subscription or a more affordable debrid subscription (i.e. RealDebrid). If you use RealDebrid or AllDebrid, one method of finding releases is using Debrid Media Manager, which searches for cached releases that other users have already submitted to the debrid service you're subscribed to. As debrid downloads, in my experience at least, are often corrupted (resulting in errors either when extracting files from an archive or re-encoding a video in MKVToolNix), the best use of debrid services is to use it with an app like Stremio to have an all-in-one streaming service.

The other paid solution is usenet, which requires a NZB download program (i.e. NZBGet), a usenet indexer, and a usenet provider. The latter two usually require yearly subscriptions, but often have better results than can be found on DDL sites or public torrent trackers. While some usenet indexers are private, there are enough that are not to make waiting for open signups for those indexers optional. The public ones include altHUB, Miatrix, and NZB Finder, the private ones include DrunkenSlug and Tabula Rasa, while NZBGeek is public but is only free during a limited trial period, after which a subscription is needed. The free ones usually have a 5 downloads per day limit without a subscription. Note that Jdownloader is not a NZB download program, but rather one for regular downloads, and would instead be used for DDL site downloads.

For torrenting you need access to torrent trackers and a torrent download program. qBittorrent can do both if you add the Jackett plugin to it, though the best seeded (available for download) releases are often on semi-private and private torrent trackers. The best semi-private to start out with is TorrentLeech, given its lax seeding requirements compared to other private trackers. Keeping releases seeded on TorrentLeech gives you points over time that you can use to boost your ratio.

While I'd recommend using a paid VPN if you choose to go the route of torrenting, it's not essential if you instead use debrid and/or usenet subscriptions as in those cases you're not re-uploading downloaded releases to other users. If you'd rather not pay for any services, I'd recommend just using a site like MovieWeb to stream releases compiled from free streaming websites. While the quality is not always as good as can be had with the three options above, it works well for most use cases.

While it doesn't have a free tier like other indexers do, NZBGeek marks the languages of multilingual releases on its search result page. Not sure why, but I haven't had nearly as much success in finding French releases on torrent trackers and usenet in contrast to their English counterparts, even for some shows that are French to begin with.

For some shows I've noticed that it's not too difficult to get around half of their seasons in 4K, with the 4K releases for the remaining seasons being seemingly nowhere, whether it be on public trackers, private trackers, or usenet. Doesn't seem to be an issue of shows only being shot in 4K after their first few seasons, as in some cases the 1st and 3rd seasons may have 4K releases without the 2nd season having one, for instance.

How often does abtorrents open registrations?

Hard to find scene releases are sometimes only available via usenet.

Thought it was for a different game at first...

Without port forwarding, torrent clients can only connect to a fraction of the total number of seeders.

Unfortunately it's a relatively new TV that just happens to not be a smart one. Having helped my other relatives pick an inexpensive Google TV powered smart TV specifically for its VLC compatibility, I would have preferred to have done the same in this case, but hopefully I can find something that'll work all the same.

I can imagine the phone-to-roku streaming method working well, particularly given the simplicity of Roku OS, though in terms of USB drive usage, past testing on a dedicated Roku TV has been mixed in terms of codec compatibility, unfortunately.