I don't think that makes sense. If Harris had happened to win through some minor change in the timeline (she came very close after all), would those people whom you call R supporters instead somehow be D supporters, just because of that minor change in the timeline?

As for "OK with Trump", I think that describes some non-voters. However, there are also non-voters who are more accurately described as "not OK with either side, indeed dislike both sides so equally that neither one seems like the slightly better option".

There is also the factor of swing states. In most of the US, your vote for President pretty much doesn't matter. You almost might as well just put it in the trash. The vote in your state is, barring a massive political shift, locked in for one of the two major candidates. Now, yes, you can still send a message by voting in a non-swing state. But it's understandable why some people would just not bother to vote in a state where the outcome is almost predetermined.