I'm afraid I've not actually done like DIY yet. My sister is one of those craft people who has like a crickit and a thermal press thing, so I'm reasonably sure it's possible with some blank cards I've bought and her sublimation printer(video), but I've not gotten the chance to test it yet.

I've also considered doing this: which is using a tool/website to put together a bunch of cards and then send it to a printer, but again haven't done it. https://www.youtube.com/watch?v=KA9pY0NNMvc

I have ordered some cards from this place, and they're not horrible, but the resolution wasn't quite as good as I was expecting. https://mtg-print.com/

For the most part, I still just take the tokens for doublesided cards and just write my card on the damn thing.