I decided to go for it. I basically followed the directions of buster->bullseye, except that I changed ‘amber’ to ‘byzantium’ in my sources.list.
I did use the two-step upgrade I mentioned above, but I got a dependency error after step 1. It involved the libc6-dev package that is the cause of discussion across the Internet. @NineX helped fix this here. I did not come across the notion of removing both the libc6-dev package and the libgcc-8-dev package anywhere else, but it worked for me.