There are fiat denominated gift cards you can buy with XMR.

Well, for the absolute best privacy and open source, you’d want Monero. But this wouldn’t let you do cards, so that wouldn’t work for you. You might be able to buy prepaid cards, but I’m not totally sure.

What seems crazy to me is how many people they managed to convince that they were private when they most definitely are not.

That might be kind of difficult. You might try something like hodlhodl or offer to buy something on xmrbazaar

Oh, that’s annoying. I hadn’t actually tried it myself. I had only heard about it.

I think somebody forked it and is calling it IronFox. So you might want to take a look and see if that’s correct.

I don’t know about Telegram, but I know, at least with Signal, it should work with web sockets, and allow you to get notifications that way. At least that’s how I get my notifications on Molly, which is a fork of signal. While not many applications support it, you might also look into UnifiedPush and ntfy which is a UP app from F-Droid.