Be careful if you have anything that autostarts that reaches out
Also, debian/ubuntu systems can easily be setup to auto update and reboot on a regular basis, leaving you manual maintenance only for the larger version upgrades.
A reboot doesn't break anything. Bugs do.
Any time I had a regression after a kernel update on a linux distro I could boot it on a prior version from the grub menu. Any time I had a regression with a software package I could rollback to a prior version. Rolling back updates is a problem that has been solved for decades, at least on linux systems.
The key with unattended upgrade is you want to have decent monitoring to make sure you never run out of disc space and do not figure it out weeks later if you have had an issue.
In the end it is easier to schedule a weekly reboot window if packages have been updated. You aren't running a single server if you are interested in 99.99999990% of uptime anyway.
Imho a regular reboot is good practice: you are more likely to remember what you did a week earlier if an app/service fail to restart after you tweaked a config file than if it happens months later.
There is no reason to be afraid of reboot when they happen on a regular basis.