Very likely Trump will win the popular vote in more than 26 states, but there is a danger than mail-in voting could cause enough confusion in enough states that they can’t certify any electors and that no one has 270 electoral votes. If the vote then goes to the House, it is by delegations. States with a majority of Republican Congressmen would vote for Trump while states with a majority of Democrat Congressmen would vote for Biden (or whoever the Democrat nominee is), while states that are evenly divided would cast no vote. So there is a danger that Trump would not have the votes of 26 delegations. In that case, who has the majority in the Senate would be critical since the Senate would vote by individuals for the next Vice President—but what if it is tied 50-50?
If it is 50-50 in the Senate, then the Constitution is quite clear here. Rock, Paper, Scissors...
In the matter of a 50/50 split Pence would cast the deciding vote. He would still be the president of the Senate till Jan 20th.