Biden's shortcomings are true and obvious. And simply voting for Biden as the lessor of evils is insufficient. BUT, it is a necessary step.
First of all, it isn't that Biden himself is evil but that he is part of an evil system—a plutocracy that rapaciously uses both human beings and the Earth itself as means to an end. This is also true, in a different form, of America's adversaries. In China and Russia, people are exploited to serve a different kind undeserving ruling elite.
But we need Biden over Trump for the same reason the old Soviet Empire needed a Gorbachev instead of a Stalin. Because Gorbachev was in charge, the Soviets did not kill thousands or even millions of protesters when the Soviet Union fell.
Similarly, our opposition to climate abuse, and other outrages, will draw a less harsh response from Biden than from Trump. In either case, we will do what's necessary to protect the planet and build a better civilization. But it'll be a bloodier endeavor under Trump.
