Hello Simon6677
As far as I can see correctly, this monitor should only support 60HZ. I also find the following info on the manufacturer's page:
Physical resolution 3840 x 2160 @60Hz (DisplayPort, 8.3 megapixel 4K UHD).
Hope I could help :)
Kind regards
In the full resolution 3840x2160 everything becomes very very small. However, you can adjust the scaling (Mac System Preferences - Display - Resolution). Then everything looks "natural". Small note: I use the display via HDMI cable on a Macbook (2017) with external adapter (no USB-C connection) and my refresh rate is not 60Hz (much lower) in this setup.