I'd be interested to see more data. I wonder if Forza is having fewer digital sales, since if you want it digitally many people would just opt for game pass, but the positive buzz generated by more people playing it because of game pass has resulted in increased physical sales. That would make logical sense to me, and seems to be something that Microsoft, Playground and players would be happy about.
For Assassin's Creed, hard to judge with just this small bit of insight into sales, but I'm curious as to whether it will ever become a consistent annual seller to the same extent it used to be. Maybe it's still doing great, since this is just UK physical data, but given the stiff competition from other recent releases and older games still commanding a big audience, I wonder if Ubi are feeling the heat.
Just speculation of course, difficult to know for sure without having access to more data.