Bookmarks and passwords are taken care of. And for the apps I’ll try to get migrated to flatpaks as many as I can while still on original system.
I also see that full disk encryption is being recommended a lot, and I don’t have any solid reasons to encrypt only /home.
I have not given much thought on Silverblue. Is it “flatpak-only”? If so I’ll need to go through my apps to see if that could work. And my backup strategy will need to change - I use Duplicacy that is not available as a Flatpak