The Ake goal, and the one in the derby, wasn't anything to do with VAR. The role of VAR in these situations is ONLY to determine a fact, is the player offside which is exactly what it did.
For both, VAR wasn't really necessary the player was clearly offside. VAR would have been used to double check other possible incidents leading up to the goal
Both goals were awarded by the on-field ref who, again for both, consulted the linesman to confirm his view that the player in question was not interfering with play.
Argument should be about the law and how it determines interfering, for what its worth looking at the criteria Akanji wasn't guilty Rashford was Yesterday the GK dived regardless of Akanji, at OT there were numerous interfering offences well argued on here
Are the guidelines wrong? Probably but they stand and most people, including the experts, don't bother to read them judging the situation on their own belief how how it should be interpreted
Coincidentally Oliver was the VAR at OT and ref yesterday