I am downloading through Mullvad, which I know doesn’t let you forward your ports. So I can appreciate that that seeder’s settings and mine might not be super compatible.
Are there any other peers in that torrent swarm? If it's just you (leeching peer) and the lone seed (seeding peer), and neither of you have ports open, then you won't be able to download any torrent data.
If there is another peer in that swarm, or another peer joins later, and that new peer happens to be fully connectable (port forwarded) then you'll be able to download the torrent data through them. If this is your situation then all you can do is try your luck and wait for another peer to come by.
Or if we rule all of that out - it's possible that lone peer just has a very busy torrent client. They could be the lone peer on tons of other torrents so it would take quite a while before their torrent client gets around to sending you torrent data. If this is the case then it's the same as above, just have to continue waiting.
The WD sales are decent if you're buying new so if you're feeling like it's time for a purchase this might be worth it for you.
I did the same earlier this year though in my case I tend to buy the current gen large capacity WD Reds & stick with them for a few years at least. When their 24 TB / 26 TB drives went on sale they actually were cheaper than what Newegg / Amazon had done with their own sales up to then so for me it was worth it.
The other thing to keep in mind, if you're in the U.S., the whole tariff situation isn't going to make this stuff any cheaper in the future.