Once a month? No. I hardly even reboot my Windows machine once a month...
Only the major releases of Windows 10 need a stop the world reboot. Those happen once every six months. And it's usually only a few minutes.
That's for a home machine. I've seen some enterprise machines take forever. I have no idea how they managed to fuck that up, but it's on the IT organisation of those enterprises, not on Windows.
I said once a month, because if you use your computer once a month there is no point having it powered on 24/7, not economical. What happens is you power it on when you need to use it, Windows starts downloading updates in the background, the next time you power on, installation starts on boot.
Those updates don't get installed at boot time. Modern Windows installs most updates in the background. The only ones that require a reboot are the big ones, every 6 months.
You lost me there. Which version of Windows will install the monthly cumulative update without a reboot?
Server 2016 (and older versions of W10) are horrendous for updates. You can have servers stuck on "configuring updates" during shutdown or startup for over 30 mins. Server 2019 is much better though.
Only the major releases of Windows 10 need a stop the world reboot. Those happen once every six months. And it's usually only a few minutes.
That's for a home machine. I've seen some enterprise machines take forever. I have no idea how they managed to fuck that up, but it's on the IT organisation of those enterprises, not on Windows.