And with all the googling and reading all manner of “blog posts” with all manner of missinformation about fooling your watch to connect to a 5GHz network (electronically impossible) the answer was right there in the list of results
I had wrongly assumed that apple watch could only copycat the phone’s wifi connection. I was wrong. I guess this was there all along or was added at some point. Actually I had no idea that there was a settings menu on the watch itself, I had always thought all config was done on the watch app on the phone. Anyway will leave this here and hope that the 3 other people on the planet with this problem also find it.