New Build, No Display on power up

Hi guys I'm hoping I can get some assistance here from more experienced heads.

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My specs are as follows, this is the first build I have done in over 10 years.

Asus B550-I Mobo

NR200P Max Case, includes 850W PSU and AIO

Ryzen 5600X

RX 7900 XTX, Sapphire Nitro+ (using riser cable 4.0)

Western Digital SN850 NVMe 1TB

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I'm certain I've built this correctly and reseated all parts. When powering up, all fans are spinning fine and everything seems to work. However there is no signal on the display via DP. I observed the LEDs on the mobo, and its cycles through all the colours and stops on green = BOOT (which I assume is normal given there is no windows installed yet).

Anyone have any idea what the issue could be? I can't even get the BIOS, zero display signal :(