Here www.bbc.com/news/newsbeat-53096057
If he says they look professional then I suppose he knows, but I don't think men's hair is all that difficult and the wives/girlfriends have had weeks to practise. We bought clippers and comb attachments and admittedly the first go on DH was a bit ropey but the second time I tried it came out pretty well. He does a lot of work Zoom calls and some people thought he'd managed to get a professional cut (although to be fair they might have been looking at him in a very small portion of their screens). There are lots of YouTube videos and a fade (which is what a lot of the footballers seem to have) is actually very straightforward.
I'm not even very nimble fingered or artistic and make a bit of a mess of doing my own make up, so I imagine that footballers' other halves who are usually very into personal grooming would be naturally pretty good at doing hair.