This was always the plan. They will contest any replacement and then only Trump will be on the ballot. AOC tried to warn you fucking people. This is why Biden needed to go over a year ago and the PARTY said “fuck you guys” until it was too hard to fucking ignore.
The convention hasn’t happened yet, there has not yet been a democratic nominee.
But yes, this is part of their plan. Even if it goes to the SC though, John Roberts and Coney Barret would have a hard time finding any legitimate originalist arguments for supporting the challenge, and have demonstrated they are not quite pure conservative ideologues.