If you saw the play in real time (not slo-mo and especially not freeze frames), it's obviously accidental. That's not exculpatory in and of itself, but should prompt the ref to examine other factors. In this case, the argument can be made that there was no fault in the initial contact between the two players, and what happened after that initial contact wasn't fully in either player's control.

But can also be argued that any studs-on-player contact can lead to a red card, so I don't really have an issue with that. The problem arises, as I described, with the VAR breaking the review protocol. With an illegally-conducted VAR review, the decision has to return to the call made on the field.