I was discussing with a friend on solutions on how to make your PC being 'never idle'. As he told me, if the PC is never idle, then Win10 won't enforce any updates/reboots.

I do not know how true is that, but when I suggested he use MouseJiggler [1] he thanked me and told me 'it worked'. It is a stand-alone/portable .exe that 'does exactly what it says on the tin'. I use it to keep away screensavers/screenlocks (on machines I don't 100% control).

[1]: https://mouse-jiggler.en.uptodown.com/windows

Edit: I keep away from W10 so I don't know to what extend this would help. I assume it would delay unwanted reboots, but I don't know the W10 update-forcing mechanism, and on the diagram depicted on the article I don't see any 'idling' criteria.