All of the ballot-counting has been under the watch of observers on both sides of the aisle, including especially multiple Republican observers. Republican observers have confirmed that ballots that arrived after the deadline have either not been counted or have been counted separately from votes received on/by election day. If those segregated ballots were included in the count, Biden's lead would exceed 100k in PA.
The actual Republican partisans on the ground with actual knowledge of what's going on acknowledge that nothing illegal has happened in the PA vote count.
Your guy lost fair and square. Accept it and move on.