The Rolling back section of this page mentions at the end of the section, after step 3, that:
Note that this will deploy the exact version as requested and will not include overlayed packages and other changes.
According to current tests on F41 Silverblue, this is not true (anymore): previously layered packages have been layered on the rolled-back deployment as well, and changes in /etc
have been preserved.
Below an excerpt of the rpm-ostree
man page, deploy
subcommand:
This will also queue an update for any layered packages.