Connect two external displays to iMac (24-inch, M1, 2021)

Hi everyone,

I've a iMac (24-inch, M1, 2021) and I want to add two external displays. One is a Dell monitor that I want to use as an extended screen. The other is a Huion Kamvas drawing tablet.

I've tried connecting each of them separately to its own USB-C port at the rear of the iMac, but only one display is ever recognised.

I then bought a USB-C to Dual HDMI adapter that I plug into the back of the iMac, but again only one display is recognised.

Really struggling to find a solution, so appreciate any help anyone may be able to offer.

Peter