M1 Macbook Pro - Dell External flicks from on to black, back and forth

Have seen other people out there with the same issue - I have 2 M1 Macbook Pro's at my house and they both do the same thing. Plug in my 2 new Dell S2721QS 4k monitors and immediately one of them will start flashing black and then come back, then black again and so on.

I am connecting these monitors using DP to USB-c cables into the USB-c ports on the machines directly.

I have tried swapping cables, no difference.

I also have a 2019 Intel Macbook Pro and the screens work perfectly for this machine everytime.

In order to resolve this issue, I keep having to adjust the display settings until the screen stops flashing, but this only works for a limited time, the next time I connect the screens or turn the computer on we are back to square one. I can also remove the cable and plug it back in a number of times, and eventually the screen stays on.