Apparently, enabling the option "Notify me when a restart is required to finish updating" in Windows Update > Advanced options also implicitly prevents the restart from occurring automatically. I would not have assumed this just from reading the text of the setting and description!
Notify me when a restart is required to finish updating
Show notification when your device requires a restart to finish updating
See https://www.tenforums.com/tutorials/8013-enable-disable-windows-update-automatic-updates-windows-10-a-post2552210.html?s=486a5969f4cef87271ea9e932484eec2#post2552210
In Settings, Windows Update, Advanced there is a setting "Get me up to date" which when enabled searches frequently for updates, downloads them and restarts so you are always updated with minimum or no waiting when restarting/shutdown. But this can restart your computer at any time without a warning before you have time to save your work! If you usually leave your computer on to complete some tasks overnight a sudden restart will stop whatever the computer was doing. I leave it on for downloads or video rendering, so a sudden restart would interrupt this so I never enable this setting. On the contrary I enable the "Notify me when a restart is required to finish updating" to prevent it restarting automatically.
And for some preview of what will happen with this setting on, see https://answers.microsoft.com/en-us/windows/forum/all/stop-automatically-updating-my-system/1e4ab66f-c610-49a3-a627-12d4e5c75210
First - make sure the notification is turned on for a restart
in Settings -> Windows Update -> Advanced options
turn on "Notify me when a restart is required to finish updating"
you will get a notification that a restart is required and that Windows will restart outside active hours.
if the device is not available outside active hours, you will get a notification like this
[Image]
with the option to Restart now, pick a time or snooze the notification.
although it is unclear from that whether there are limits to how far out you can select a time or how long you are allowed to snooze. But it sounds like it will get you basically back to the status quo I remember from Win10.