I have bought a TP-LINK TL-WDN4800 which works first time with kext IO80211Family.kext. Cost £20 on eBay. Yes, I am a cheapskate. This is my son's machine that I made for him in 2014 - so pretty good longevity to bring it up to Mojave. There's no real incentive to bring OSX right up to date because he would lose the use of a number of apps from Adobe and others that would be costly to replace.
Thanks to EdHawk and Feartech, this chapter of struggle is now done and my son gets a rejuvenated Hackintosh back to make music and video and (apparently this is important) games on the new Windows 10 boot.
I could bore you with stories of my B.Sc in Computer Science from 1975 (our MBR was on paper tape, etc, yawn) but I won't.
And the time I bought a 20Mb [sic] disc unit to go with my PDP11 in 1979 and hurt my back carrying it up the stairs....
Thanks again you two.