The fewer packages you have installed, the easier it is to upgrade. So if your stuff is containerized, upgrade should be mostly painless.

In my history at least, dist-upgrades have never themselves been a problem, not even when doing such things as a x86-to-x64 crossgrade upgrade (from Stretch to Buster, back in the time). The problem usually comes right after, with the first reboot, when something does not generate correctly in Grub or the new kernel's initramfs is lacking a specific module, or a given mariadb flag you were counting on is no longer added by default, or somesuch. So always have a rescue boot ready.