A quick online check showed that your CPU has Intel HD Graphics 530. The motherboard has the output ports for on-CPU graphics.
I don't own Intel, but it seems if you simply remove the GPU and use the video output port on the motherboard, it should boot up.
I do know on my AMD MBs, one can turn off the CPU graphics in BIOS, if on-CPU graphics exist. Can't say if your MB has on-CPU graphics disabled. But, I imagine they are not disabled.
Just speculations for what they are worth.
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