Q: why photo upload says China?

Have you checked the latitude and longitude of the GPS coordinates of your photos?

If you export one of the photos to the Desktop, select it, then use "File > Get Info" the Info panel will show you the GPS coordinates.

The mixup of Venice Beach and Jiangsu looks like a an error in the longitude - the latitude of the places is roughy the same, but the longitude differs in the sign - Jiangsu has roughly the same longitude as Venice beach, but with the opposite sign - eastern longitude instead of western longitude.

If the GPS coordinates of your photos are correct, It might be a transmission error, when Photos queries the location from Apple's Places database, then it will correct itself soon, or the entry in Apple's places database is wrong.

When I enter these coordinates as the location of a photo   33.984531, -118.472949. in the Info panel

Photos will show the correct place name Venice City Beach: