Delta ring but no new dashboard experience while people not In the preview programme have it?

In my understanding the Dashboard experiment, A, B, C selection, is totally random.

As "Both consoles say their OS Version is (19h1_release_xbox_dev_1911.191028-1335)" your consoles are either in the Beta or Delta ring.

Both those rings and Omega ring are getting a preview update News release notes Beta Delta Omega
Insiders today, which you can manually start or wait until it becomes mandatory.

After you do the update, if you want to change rings, it will be the perfect time to change as all those rings will be on the same release. Subject to eligibility.

It's still rolling out so at some point you'll get it on your Series S.

Only if you are in a Insider preview ring! ASA, Alpha, Beta, Delta or Omega.

There has been no notification that the new dashboard has been released to GA.

They've selected a few in the
different rings that are testing the new dashboard as far down as Delta ring, actually. But not everyone.

It happening to me as well, it's casue of the preview programme and the new dashboard

If you are part of the subset Alpha Skip Ahead preview that has the new Dashboard, use the Insider Hub and Manage option to change to a lower preview ring, eg Beta, Delta or Omega.

Or opt out of any previews and unenroll the console from any previews and install the General Availability public OS.

Be aware that changing previews or opting out will require a Factory refresh of the console. You will need the account details of any profile that uses the console.