Thanks for reaching out. We are here to help.
Could you please share the type of images you are working with, JPEG or RAW? Have you recently imported a large number of images? Does your Phone have sufficient free storage space? Have you tried logging out and logging in again?
Before you uninstall Adobe Lightroom on your Phone, please log on to Lightroom Web (https://lightroom.adobe.com) to check current Sync issues on the left part of the screen.
If there are any sync issues, click on them to know more, find the original for those images, and back them up safely before you empty the Sync issues from Lightroom Web and then re-install Adobe Lightroom on your Phone.
We are here to help.