At this moment Biden leads by almost 29,000 votes in Pennsylvania with 96% tally.
What makes you think there are enough of the late received ballots to change the outcome, even if they are all invalidated, and even if they were all for Biden?
This article says it is believed that there are 3,000-4,000 such affected ballots. And as a practical matter, some % must be for Trump, so removing them all will affect both candidates.
https://thehill.com/regulation/court-ba ... pa-ballots