Once I decided I was quitting Mint, I saw no reason to get sentimental about it or procrastinate. I did the heavy lifting this past Sunday, and now I am in the yak-shaving stage. AKA the fun part. It’s revelatory, how so many of the things I thought were just a part of any desktop Linux, are actually Mint- or Ubuntu-specific.
I would be remiss if I did not pay a huge shout out Aptik by TeeJee, without which I would have had to do dozens more hours of real work. Aptik makes migrations between Debian-family Linux distros way easier than we have any right to expect.