Only one event, loss of multiple seats will register. Of course some of them will double down on sinister instead, if they're fervent enough
doing The Lord’s work.
Still, the party's fissures will expand in the GOP among groups like the diehard Trump fans (if they flock to anything short of Trump himself), the rather cynical fans of policy on taxes and deregulation, and the "true conservatives" of which there are still a lot, even if some of those have meanwhile voted for Trump in 2016 and may do so again out of a desire for a conservative Supreme Court.
(One of McConnells wonderments is whether Rs who are in that last group will still vote for Trump if the nomination of Barrett is confirmed ahead of the election.)
How badly that ongoing internal disruption will go from 2021 onward for the Republican Party --per se, as a party listed on ballots-- will depend on things like the outcome of the presidential race, reactions to that, the outcome of Congressional races (particularly the Senate if there are some close or contested or slowwwww counts which prospect is likely) and reactions to that.
Some of the reaction to 2020 elections will be via trips to court, no doubt. But some of it will be a continuing nightmare for the Republican National Committee no matter how those matters are resolved. As has been noted after their convention in August this year, quite aside from the disruptions caused by covid-19 and an altered look and feel to both major parties' conventions, the Republicans turned their event into a love fest for Trump: the GOP's platform issues were conveniently left waiting in the wings for the poor sods who have to come up with something next time around.
The Trump era has split Republicans on fundamental policy issues like trade, health care and now on best practices for emerging from the pandemic as well. The party's a mess, and now comes Trump bringing covid-19 back into focus at the worst possible time, with early voting just commencing.
Many, perhaps most Republicans may choose not to vote by mail, for all the reported reasons including Trump's savage bashing of that mode and his crony USPS chief in there still discreetly trying to make sure things will go,...sloooowwwly. So the choice to cross party lines if they wish to do so now is still open for most of the right leaning electorate.