External monitor using iGPU instead of the dedicated one

So I bought a monitor to use with my laptop, and a Thunderbolt 4 to DisplayPort 1.4 to be able to use it. However, the monitor will only run with the iGPU, if I disable it in device manager or change display mode to "Discrete GPU only" in the bios, the monitor won't receive any signal at all. I used to have another monitor and that one worked perfectly fine as it was using HDMI. Is there any way to force my monitor to use the discrete GPU or is that just not possible with Thunderbolt 4? Also, would buying a HDMI 2.1 to DP 1.4 cable fix my issue? I'd rather not buy another cable but if that's my last option, I will. Thanks in advance!