The old Hue app still works and I'm also using Hue Essentials, both without any account.

I have a Hue bridge of the 1st generation and a few years ago, the original app was showing pop-ups, that I need to get a new bridge because of the new app that will no longer support my old bridge. So I just kept the old app and the old bridge. Works like a charm all offline.

When I added a motion detector two years ago, the old app didn't find it for setup. That's when I tested the alternative app Hue Essentials and it works just fine offline.