Does that math check out? How about the math that shows how Harris didn't even peel off an extra 1 percent of registered republicans, despite pandering so hard to the right.
I don't think blaming voters is a good idea. There were signals that people would be more likely to vote for Harris if she, for example, agreed to stop sending arms to Israel (more than the voters she'd lose by doing that). The campaign ignored that.. if they tell you what they want and you ignore it that's kinda on you. Trying to rehab the Republican party ("Country over Party") instead of going out there and hammering home her policy, how she would make things better for voters... there were lots of mistakes made.
It is almost always the non-voters that are the problem. In this case it was a combination of demographics that just chose not to vote at all which led to Trump winning.