..within a torrent, and apparently messed up selecting what I did want. So nothing was selected when I gave it the go-ahead to start downloading.

Amusingly, perhaps, Tixati went straight into seeding mode - with nothing downloaded and nothing selected to download!

...

Secondly, I would donate, and have tried to, but because my country has banned PayPal, I can't make payments even via VPN (credit card from the wrong country, per PayPal). And I am truly sorry, but I'm actually a bit too old-school and isolated to get my brains around any of this crypto stuff; I'm sure it's easy if you know how, but...

Surprisingly that's exactly how it works. You may not have anything downloaded but you still have metadata and can upload it to new peers. You can become a middleman to initiate a connection between 2 other peers (NAT hole punching) while seeding at 0% too! It's not entirely useless even if you look like a spy to other peers on their listings.