I use a USB-C cable for monitor - tablet connection. It works directly, but with the older Satechi model there was no display (was it possibly earlier with USB2 only for power?). Can this successor model also recognise the monitor signal via the second USB-C port?

I just got an answer from Satechi that the USB-C port only works for power. So if you connect a hard disk to the adapter does it work?

Yes, it works for that too. It is a very good product.

I do my Time Machine backups with it, without any problem