Question about i-tec USB C to

You can use this adapter on macOS, but unfortunately, macOS does not support MST technology - that means that only 1 monitor will have an extended screen. If you connect 2 monitors, then both monitors will show the same picture.
If you want 2 external extended screens, then you have to use either U3DUAL4KDP or TB3DUAL4KDP.

Yes, it is. But if you want to connect two monitors, you can only mirror the image on this one and not expand it. So if you want to display something else on both monitors, this one is not suitable.
It only mirrors the MacBook on both screens.