There are few tools which can be helpful in this case:
- https://github.com/SitecoreUnicorn/Unicorn
- https://doc.sitecore.com/xp/en/developers/101/developer-tools/serialization-plugin.html
- https://www.teamdevelopmentforsitecore.com/
In general the idea is to serialize a set of items which you are working on (not entire database) to disk as text files. This will allow you to version them using git, make them a part of the deployment package and install them on the staging server.