Unable to completely sync my iPhone with my MacBook Pro

You may have to investigate use of iCloud along with other aspects of sync.

A login via iCloud should allow another means to connect these products.

• About syncing your Mac and your devices - Apple Support

https://support.apple.com/guide/mac-help/syncing-overview-mchl923c1147/mac

• How to Sync iPhone to a Computer - Lifewire

https://www.lifewire.com/sync-iphone-to-computer-2000128

• Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support

https://support.apple.com/en-us/HT210612

(Sync with iTunes: after certain point, no longer works; or functions differently)

In the course of handling iOS files of various types, you may need to backup contents.

Suggestions how/when to use computer or iCloud are covered in article; & then some.

• How to back up your iPhone, iPad, and iPod touch - Apple Support

https://support.apple.com/en-us/HT203977

From reading few symptom indicators mentioned, I find difficulty resolving causes.

Perhaps another helper with experience with your issue(s) may see situation better.

Good luck & happy trails!🌞🎣