Yes, you actually can use Office 365 from a local account — I’ve done something similar myself. The key thing is that Office activation is tied to your Microsoft 365 account, but it doesn’t really care which Windows account you're using as long as you sign in to Office itself.

So here’s what happens:

If you log into your computer with a local account (say during an internet outage), Office apps like Word or Excel might not work right away unless you’ve already signed into Office from that local account before — while you were still online. Basically, you need to activate Office once under that local Windows profile.

What I’d recommend is: when you do have internet access, log into the local account, open Word or Excel, and sign in to Office using your Microsoft 365 credentials. It’ll activate Office for that local profile too. After that, you can open and use Office apps just fine even when you’re offline — Microsoft gives you a good 30-day window where it doesn’t require an internet check-in.

As for licensing — you’re totally fine. Microsoft 365 personal is licensed per user, not per Windows login, and as long as you’re the one using it on your own device, you’re within the rules.

Just a heads-up: files from your other (Microsoft) account might not be immediately accessible unless you saved them in a shared folder or somewhere like C:\Users\Public, but that’s an easy workaround.

Hope this helps!