I think two things can be true at the same time:
1) It’s probably a penalty (just) because of Dumfries’ studs going toward Kane’s foot, rather than away (which would be the case if he was trying to block the shot, rather than nick the ball away)
2) England were very lucky that VAR decided to have the ref over to watch the incident back—most often those are not given as penalties when the player gets the shot off (as illustrated by the 20 or 30 non-penalty studs up challenges in the box we were on the end of last season).