Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Here's a slightly new thing. If I open Word and sign out, close Word, then open task manager and find "Service Host: Web Account Manager" and end that task, when I then open Word again I can use Word. It now says that it is an unlicensed product, but it retains functionality. It's only for a short while though until the "Service Host: Web Account Manager" restarts automatically after a few minutes. Once that service restarts, the Office product deactivates again and you get the pop-up again to sign in.
EDIT:
I thought maybe disabling the service would work (instead of ending the task), but alas. Within task manager, I went to services, located 'web account manager', and disabled that service (all while signed out of Word). I restarted my laptop and opened word. It still deactivated my Office product and showed the pop-up window to sign in, only now it gets stuck after the screen where you enter your email address, you're not provided with the screen to enter your password. You can only proceed with the 'web account manager' service enabled. I'm assuming it's then the 'service host' task that's is showing the pop-up sign-in window.