Thinking out loud here: McConnell's timeline for confirming Barrett by Oct. 27 depends on Dems blocking the GOP's second covid relief bill that he is bringing to the floor right before Barrett. But what if Dems don't do that?
Strategy A (don't block the covid bill until a later stage):
Oct. 22: Covid vote: Cloture on motion to proceed (LET THIS PASS)
Oct. 24: motion to proceed
Oct. 26: Cloture vote on bill (block here)
later on Oct. 26: cloture filed on Barrett
Oct. 28: Cloture vote on Barrett
Oct. 30: Final vote on Barrett
This obviously wouldn't stop McConnell. Even if Schumer is playing games with various motions, McConnell still has several days to spare here.
The even wilder strategy - let the GOP actually pass their covid bill:
Oct. 22: Covid vote: Cloture on motion to proceed
Oct. 24: motion to proceed
Oct. 26: Cloture vote on bill
Oct. 28: final vote on bill
later on Oct. 28: cloture filed on Barrett
Oct. 30: Cloture vote on Barrett
Nov. 1 (?!?) : Final vote on Barrett
This would get a little dicey for McConnell - Nov. 1 doesn't offer much lead time if there's some sort of quorum issue or if someone gets sick, and Schumer might be able to use up a day through motions and such anyways. And eventually, GOP senators up for re-election have to head home for their victory parties or concession speeches. This could conceivably delay Barrett to after the election. It would not stop her confirmation - but it would make it the first vote of the lame duck rather than the last vote before the election.
Is it worth it for dems to do this?
Yes, because the optics of confirming Barrett after a Trump defeat are absolutely terrible and would make even the most wishy-washy centrist Dems open to court-packing.