ninowebs
If you're experiencing sync issues while testing. (i assume you're testing locally) Then there's most likely an error in your setup. Make sure you didn't miss anything by looking at the multiple examples that are provided by Construct.
If you setup a "sync object position", means that the Host will send the position data of said objects to all the peers. Means, if the objects never move Host side, then it will simply sync non-moving objects.
To make them move, Peers must either send their movement inputs OR their positions to the Host. The host then either moves the objects OR updates their positions for himself. Then the host will sync these movements to everyone else.
If you still encounter issues, and need help, please share your project file so we can take a look at it.
Multiplayer Examples
https://editor.construct.net/#open=multiplayer-pong
https://editor.construct.net/#open=multiplayer-game
https://editor.construct.net/#open=multiplayer-chat
Multiplayer Tutorials
https://www.construct.net/en/courses/online-multiplayer-construct-12