Yes. Barring any truly bizarre turn of events (though it is 2020...) there is really nothing progressives can now do to change the fact that either Doanld Trump or Joe Biden will win the election. The only influence progressives now have is which of those two horrible choices it is. Well, progressives in swing states anyway.
And as marginal as the differences in their platforms sadly is, it is an absolute fact that there are differences and that Biden's platform is better less awful than Trump's. Both are harmful, but Biden less so. Trump is largely immune to public pressure, Biden can be moved at least some times on some issues. I've yet to see a convincing argument that not voting or voting third party has benefits that outweigh those differences.
You don't have to pretend to like Biden, you don't have to ignore his many, many glaring flaws. Just remember that all political change worth a damn comes from the bottom up not the top down, and an election is the process of choosing your opponent, not your avatar.