I've been slamming Russian/tankie "both are bad" commenters for a while here; check my comment history before you judge my response here:
I don't know about a campaign but the sentiment is hardly astroturfed. A lot of leftist (not liberal or tankie, actual leftist) pundits and influencers think Biden is a bad look for normies and certainly doesn't energize voters. This includes people from all varieties, who are not always in agreement otherwise; like Emma Vigeland from Majority Report (and probably more people from that show), Hasan Piker, Vaush, Cenk from TYT... Whatever you may think about any or all of them, they're all in agreement on Biden being replaced.
These people are hardly part of an echo chamber, they regularly come at odds with one another, and none of them are part of an astroturf, and definitely not from GOP.
Note that all of these people would still advocate for voting Biden as long as he's the candidate. But their concern is about voter turnout after his horrible performance in that debate. This is a country who elected W. Bush, because they'd like to have a beer with him. How they look and come off unfortunately matters, sometimes more than the content of their messages and even accomplishments.