Something that's unfair to me is something that gives an unfair advantage to one side or another. Like for instance drawing up districts in a way that is specifically designed to concentrate or disperse demographic groups who favor one party or another. Giving as many people the chance to vote as is practical is NOT unfair. Were only Democratic absentee votes counted? Were they told how to vote? I don't think so. Your problem seems to be that the maximum amount of people were allowed to vote. I find that a weird problem to have if you are interested in fair elections.
So, I'll ask again. How is it fair to anyone that we allow one side to continue to vote after a deadline that is so well known in advance that we know these dates for the next 100 years?
Shall we start collected votes from Republicans after the deadline day and continue to collect them until such time as we can announce the GOP candidate as the winner?
That is what happened here.
If you truly want every vote to count, then we need to keep allowing people to vote every day of every year.
What I find unfair is that when the polls closed, elections that had been called for GOP members were overturned by additional voting after the fact.
If that had happened to the Democrats, as much as I detest 90% of them, I would be howling from the rooftops that the law that allowed this was unconstitutional.
If the GOP won't challenge this, then they better find a way to do what the Democrats did and ensure they have a cadre of voters sitting in the wings ready to vote should their guy fall behind on election night.