Messages on my Apple Devices not syncing up.

Let's face it, this is broken. I have three devices I use regularly: an iMac Pro, a MacBook Pro, and an iPhone 14. All are updated to the most recent operating systems. All are logged in to my iCloud account. All have Messages enabled in the cloud. All have syncing enabled. In general, yes, the BLUE messages sync no problem. Messages coming from non-Apple senders DO NOT SYNC. Are they supposed to? Theoretically, yes. But if I don't use my laptop for a period of time, I have a flood of old messages that I deleted either on my phone or on my iMac Pro showing up as unread.

To add to the frustration, USUALLY if I delete a non-Apple SMS from my phone, it will also disappear on my iMac Pro, but NOT SO with the laptop. This is frustratingly bad.

Has anyone figured out how to actually make this work across a spectrum of devices?

Thanks.

[Re-Titled By Moderator]