iOS 26 messages - somewhere between sluggish and unusable

New iPhone 17 Air updated to the latest iOS 26. The message app is having all kinds of problems. It may or may not start (sometimes crashes back to the main UI). If it does open, it's unusably slow - like clicking on a message to open it will take a minute or more before it opens.

I gave it the benefit of the doubt and thought maybe it was just the iCloud sync taking a long time on my new phone. But 3 days in, the problems remain. And looking at Settings/iCloud/Messages in the Cloud, the sync is complete.

I even tried a complete restore of my phone to see if that would fix it. Even after the iCloud sync completed, messages is still dog slow (but at least I haven't see it crash today).