There can be no valid President in the four years after noon Inauguration Day 2021 short of a Constitutional Convention because so many of the elections were not conducted in the manner specified by state legislators.
Even if enough votes were found, Trump would be every bit not entitled to the Presidency as Joe Biden. Congress can’t fix the election at this point. It was up to Pence and Pence refused to sort things out despite the clamor of thousands on the streets of DC on January 6th.
Come January 20th, 2023, the serving members of the US military can not legally be paid.
Make that can not legally be paid by the federal government.
State governments might be able to pay them.