It all depends on the outcome of the election, of course. If they retain the Senate, and Trump wins, then no one will care if they vote on her during the lame duck.
If they loose one or both, and still try to ram her through then, they may face a lot more trouble, and a bigger response from the Dems.
Their best bet is to do it before November 3rd, and they know it. Which is why they're rushing to do so.
And yes, they have all of October. But that all depends on what happens. If Trump and these 3 senators don't have major issues, and just have to quarantine for 14 days, then yeah, nothing changes.
If any of them get critical, then yeah, things can get unpredictable.
Tempting as it is to hope for that, I'd rather they not be stopped by someone's I'll health, because all they'll do is draw the wrong lessons from it.
If they are going to succeed before November 3rd, I'd rather they do. If they do it, and Biden wins, a stacked Supreme Court is the push the progressives need to get him to okay removing the filibuster, adding DC and PR as states, and to expand the court. I think that's a better long term strategy anyway.