I was thinking of getting a wifi card like that, but can’t seem to find any.
ath9k supports N, so I’d consider it modern at least, since I think the vast majority of the population still use it.
N is not modern in any sense of the word. I think 6 is more used then you would think. All ISP I know are giving out 6 access points and have for awhile.
I install residential and business internet for a living and I have yet to encounter a single AX AP operating in the wild (yes I check every time, and yes my devices support it). And our own routers only do N.