Yes, Bob Gale confirmed that he based the character on Trump. The over-the-top aesthetic of Biff's Pleasure Paradise Casino & Hotel in the alternate 1985 was specifically inspired by Trump's signature style of the 1980s. The gold-heavy decoration, the massive portraits of himself, and even the architectural style were meant to parody Trump.
He didn't even need to do that. The complete removal of accountability for anyone wealthy over the last half-century along with subversion of all major media did everything for him. He just had to be born wealthy and racist, and refuse to pay people that he signed contracts with. He should have been a pauper decades ago but all institutions that could or would do so have been defanged.
Deal! I'll warn everyone about the climate crisis and we will have changed the world being warned early and the world will be saved by learning in the 80's of the danger ahead!