I have a 2020 (Intel) MacBook Pro 13-inch, with the 2GHz i5 and 16GB RAM: I've connected it to a Dell U2720Q 4K monitor: I'm using the USB-C to USB-C cable which came with the Dell to power the MacBook and send the video signal. The built-in display is (integer) scaled to 1280x800, while the Dell is set to 'Default for display', which is 1920x1080 logical pixels. The USB-C cable is plugged into the front right Thunderbolt port.
The problem I'm having is that the external display is refreshing at 30Hz (when I power it on, the little Dell interface tells me that). It feels very choppy and unpleasant. The built-in display doesn't have this issue, and is running at 60Hz.
Is there anything I can do to force 60Hz from the external display?