I love that on my arch setup, I update every single day, usually more than once, and doing so almost never requires me to powercycle my computer.
There is occasional weirdness if you don’t powercycle though. In particular, certain KDE updates will make the desktop misbehave until you reboot. I get where you’re coming from though. Quick updates and the ability to decide when you want to restart means that I have no qualms about updating frequently.
I am on Arch too and pacman -Syu is usually a snack I have with my morning tea.
You can log out, then CTRL + ALT + F1 , log in and run the update command. If there was no kernel update, you don’t have to reboot. If some service got updated restart the service (if that was not done by the updater.) Then you can switch back to the graphical session usually by CTRL + ALT + F7) and log in again.
