how to synchronize local and remote database?

Writing update scripts that will synchronize two databases manually is quite a risky job. You can maybe try to compare these by creating scripts for all objects and then use a file compare tool to find the deltas between the two schemas and change it. But for even a bit larger databases I would not recommend this method since it’s quite easy to miss some change

using some third-party tool is probably the must here, so you can try ApexSQL Diff or free MS SSDT

ApexSQL Diff can use database backups, script folders, source controls, and proprietary snapshots as data sources. It supports automation via CLI

Disclaimer: I'm working for ApexSQL as a Technical Support Engineer