Doorbell not working on Mesh Networks

There is a great thread from 2018/2019 on this topic, but I'm hoping there are updates now.

I have a new SS system, and trying desperately to get the doorbell on my wifi mesh network. (ATT service w/ their 'smart' extenders)  I have tried:

1. Changing name on 2.4 ghz network to isolate - doorbell won't connect
2. Turning off 5 ghz signal to force onto the 2.4 -- doorbell won't connect
3. Replacing the doorbell unit - in case it was defective -- new doorbell won't connect

Have re-start and renamed everything multiple ways, and I cannot get the doorbell on my wifi network.  It has never worked, although I've tried resetting the doorbell as well (small button on the back).

I really do not want to invest another $30 in another extender that is 2.4 only with a different network name unique to the doorbell--feels silly, and I think will break the integration with my base unit (?).

Any other thoughts?  Neither AT&T nor SS support had any more advice for me and I'm sick of waiting on hold...