Trump can use his special ops Monday to interfere with electors. He can try to get republicans in the key states to stop electors from signing. He could try for an injunction.
If they sign, he can revamp Texas suit and file on his own, but then SCOTUS lacks original jurisdiction; he'd have to go through each state first.
On January 6th, he could try to stop Congress from certifying elector count. Senate could refuse to call a vote.
On January 20th, he could get Kavanaugh or Tomas or Alito to swear him in, regardless that Biden is sworn in by Roberts.
I'm sure more is still afoot.
Trump will, at minimum, do everything he can do his followers see Biden as illegitimate... The new "birther" ploy in effect. 4 years of Trump screaming he was cheated and digging more hate out of his people.
America is a nation of selfish, uneducated, self-deceived, mean spirited, egomaniacs.