Forum Flora Germanica

Plant net brings up Frailea pumila, even body rib count matches to that, on the other hand Frailea pumila at wiki does not look like it at all.
Sold by namely Decorum, produced by winco holland - no latin names on packaging, anything on their pages accesible to search.
http://agrozoo.net/jsp/Galery_one_image ... b007854876

You may probably want to try a forum dedicated to Cactaceae, e. g. https://www.kakteenforum.com/ (no idea if it's good or not).

Yes, it is good.

Or try to find a similar genus in llifle:

https://llifle.com/Encyclopedia/CACTI/