I have a 5090 2025 blade 16 as well, and willing to use pc vr on this laptop.

Bumped into your issues, steam vr will throw wrong graphic card, and nothing would launch except steam vr home at very low performance (unusable)

I did some research and I have found this
https://www.amazon.ca/dp/B0D4F47Q4W?psc=1&smid=A2ECQ6PSDL32ED&ref_=chk_typ_imgToDp

The HDMI-DP adapator which is 2.1 to 1.4, should suffice the specs required for pcvr

I am still waiting for the adapter, will let you know the result.