Hello aperson15,
Thank you for reaching out to Apple Support Communities.
You can sync your messages via iCloud. Verify your iPhone isn't already synced, then sync your Mac:
"Set up iCloud for Messages on your Mac
- In the Messages app on your Mac, do one of the following:
- macOS 13 or later: Choose Messages > Settings, click iMessage, then select Enable Messages in iCloud.
- macOS 12 or earlier: Choose Messages > Preferences, click iMessage, then select Enable Messages in iCloud.
2.Select which email addresses and phone numbers you want to send and receive messages from on your Mac.
Any messages currently stored in iCloud are now accessible on your Mac, and any new messages you receive on your Mac will be stored in iCloud.
Note: If you want to see SMS and MMS messages on your Mac, see the Apple Support article Forward SMS/MMS text messages from your iPhone to your Mac or iPad.
3.To see Messages stored in iCloud, open the Messages app.
Note: If you want to turn off Messages in iCloud on your Mac, deselect Enable Messages in iCloud. You can choose to disable Messages in iCloud for all your devices, or just your Mac."
Additional details can be found here: Set up iCloud for Messages on all your devices
After synced your Mac, verify they all appear and your messages are not set to one year. Then set up your iPhone to sync with iCloud.
Let us know if you run into any issues.
Cheers!