Letting in the alternate is worse. Without question. I agree Biden and most of our political apparatus are problematic. But getting rid of Biden won't change it, and will make it worse.
Here's a hypothetical for you to answer. Would you vote to kill 100 people, or 10 people. Or choose to virtue signal, not vote, and have 100 people killed anyway. But tell yourself that you're innocent because you didn't try to help.