Why do Democrats have a much worse party switching problem than Republicans?

[Florida Man for Crime]

The reason is because the Republican party does not have broader principles or values, beyond "me, me, me." So people who join the Republican party in the first place (especially as politicians) do so in order to do what is in their own personal or financial interest.

Consequently, they can never have a principled reason to leave the Republican party in the first place, because the Republican party does not have principles over which to leave it. On occasion, Republican politicians may leave the Republican party for reasons of self interest. Arlen Specter was an example of this, but it is rare when doing what is in your own personal self interest conflicts with the Republican Party, because the Republican party is fundamentally about self-interest.

Also consequently, the only way it is possible for politicians to leave the Republican party over principles, they do so not over Republican party principles or over policy or anything like that, but rather over more fundamental principles which are American principles rather than Republican principles. For example, Liz Cheney, Adam Kinzinger, and the like. But even in this case, they do not generally (technically) leave the Republican party and don't start saying they are an independent, they just do one thing (in isolation) in opposition to it such as supporting the Jan 6 committee, or possibly don't even actually do anything in opposition but just verbally speak against it and that's all (like Jeff Flake).

This is also why Kyrsten Sinema really belongs in the Republican party, not the Democratic party. Because for her, it is all about "me, me me."