I get garbled/garbage characters (weird font?) when I try to manage payment methods (I can't get past this screen to purchase a song*):
I also got this screen at one point trying to open an apple music link:
Using latest iTunes app from Microsoft store on Windows 10.
"For you" | "Try it now" also shows junk.
(*) Eventually I was able to purchase a song by guessing what the various fields/buttons were supposed to be. But obviously something very wrong. And yes, have rebooted etc. etc.
At least one other user has reported this: https://discussions.apple.com/thread/8066958, however the suggestion (starting iTunes in safe mode) didn't help.