I've been thinking about this today:

"I wonder what the real figure is since 90% of their exertion happens in training."

Training is nothing compared to playing a competitive game. That's why there is a concept of "match fitness". For example in Football Manager, which is pretty realistic and they work with a lot of top coaches, if you train a player like mad but don't give him competitive games, his match fitness will drop and keep dropping.

I agree that there might be a lot of hidden things going on (quite honestly the BLM race baiting BS, the woke crap and the whole Covid narrative means I no longer care about football: despite my beloved Leeds United getting promoted, I didn't watch more than five minutes of Match of the Day last season - what I did see of it made me switch off immediately).