Persistent issue with messages syncing in iCloud on iPhone 16 Pro Max running IOS 26 (non-beta)

I am having an issue with my messages refusing to sync with iCloud services. I currently have around 40 thousand messages stored in iCloud equating to a little over 5GB of stored data. These messages refuse to sync to my phone. I've upgraded the iCloud storage so space isn't an issue. I have the 16 pro max and run latest release of IOS 26. Phone is charging and on wifi overnight every night so plenty of opportunity for phone to have synced 5GB of data. Issue is that selecting sync now in settings shows status "syncing" for about a second or two and then reverts back to "not syncing". There is no time stamp for a previous sync or any indication it has ever synced properly. I have tried every troubleshooting step out there that the internet suggests and that I can think of to include (repeated a lot of these on my MacBook as well):

• Restart phone
• Factory reset phone, setup as new phone
• Turn iCloud for messages off and on again
• Disable and delete in messages settings (get error stating unable to complete at this time)
• Reset network settings
• Ensured phone number and email are correct, match across devices
• Both enable and disable the message filtering settings
• Probably some other steps I am forgetting as well

Issue persists where syncing refuses to happen. Looking to see if anyone else in the community has experienced this problem. From one post I've seen online, this may be a known issue with Apple and IOS 26 with no resolution but hoping maybe someone has discovered a workaround or solution.