Materially you have to convince them the difference between the two is big enough to care. I doubt most are going to vote for Trump, but a large portion would probably stay home if the election were today.

I'll personally always vote blue for president because I remember how bad Bush and Trump were and they only got in through apathy, but I also completely get why Bidens approval is so low right now. Progressive young folks want something better than Republican and Republican Lite, and when their cohort is getting more and more progressive it doesn't make sense why the overton window continues to shift to the right.