Debian admin here. Even Debian gets regular kernel upgrades that like a reboot afterwards. Security updates are more important than uptime. Also regular testing for clean recovery after a reboot is a must so a power outrage doesn’t bring any new surprises with it. Also test your backup restores regularly.

Novice homelaber here, is this just a case of apt update & upgrade or is there different commands for security and kernel updates? Also what’s your preferred backup/restore software? Thanks!

Nope it’s just apt update & upgrade. Iirc apt tells you when the kernel was updated and needs a reboot as well.