It's a clear challenge on the ball. Had he taken out VVD well after a whistle had blown (regardless of offense) then you can have that discussion because then it's no longer a challenge on the ball, but in this scenario you can't just flip it to VC because an offside offense took place prior.

You CAN send off for SFP immediately after a whistle for a challenge on the ball. This happened with Richarlison, because he technically made the challenge after the whistle was blown for the foul with Mane. I don't remember the year this was changed, but it was done so that challenges that started outside the field of play but resulted in UB or SFP just off the field of play would still result in a sanction.

The issue is that offside has a line item exception for fouls that occur after the offense and doesn't indicate anything about sanctioning for said foul.

edit: BTW, none of this excuses PGMOL. They continue to be shit.

Its not that I would consider it VC.

In order for it to be SFP, all the requirements for a foul must also be met. Because the ball is not in play, it cannot be a foul, therefore it cannot be SFP. It gets upgraded to VC.

That's why they won't retroactively punish it. Because VC comes with a longer suspension.