Nincs ebben a monitorban véletlenül egy olyan beállítás, hogy usb priority: high speed/high resolution?
De van, de van! :) https://www.rtings.com/monitor/reviews/dell/u2723qe#usb
"If you want to daisy chain using the USB-C ports, make sure to set USB-C Prioritization to 'High Resolution' so that you can get two monitors at 4k @ 60Hz with 8-bit color depth. The daisy chain capability stops functioning when you set the color depth to 10-bit. Additionally, if you set USB-C Prioritization to 'High Data', both displays have a 30Hz refresh rate."