The point is that in the future, TikTok / Google / whatever will have to be more careful with political ads, because they can be bad for business.

Whatever your opinion on the candidates is, it's a fact that many people didn't consider the election results legitimate. In a situation like that, it's impossible to make them legitimate by any administrative action. Courts can make the results legal, but legitimacy is something people decide on their own. If legitimacy is considered important, the only way to regain it is to run new elections. It may take a long time and many attempts, and it may not work at all. But you can't have legitimate elections if the losers don't accept that the elections were fair and they lost.