TXT not consistently sycn-ing across iPhone and MacBook Airs

I have a iPhone 14 IOS 16.3.1 and two MacBook Airs Ventura 13.3.1.

I have recurring, sporadic problems with text threads -- outbound and inbound -- not syncing across devices. My iPhone is always correct and full. The Air's regularly do not fully sync. I regularly use iMessage / Preferences / iMessage / Sync Now. But this does not update the thread nor solve the problem.

This seems to primarily happen w/ SMS messages, where at least one member of the channel is not use a Apple device.

I have stopped / restarted iMessage on iPhone and Macs. I have confirmed iPhone Settings / Text Message Forwarding is set to Yes. However, this setting lists ONE device (Mac Book Air). I have 2 Macbook Airs - should there thus be "2" here or is this a categorical listing?

Guidance will be much appreciated.

DP