Apollo fork of Sunshine is amazing

Found here, I think the developer is on this sub too.

What's great about Apollo? It does what Sunshine does, except it will automatically create a virtual display on the host computer with the same properties as the display you are streaming to (resolution, refresh rate, SDR/HDR). No more mismatches between host and client displays, no need for a dummy HDMI plug. It just works.

My monitor on the host PC disconnects when it's turned off, but with Apollo, I don't need any display connected - it will create a virtual display and stream from it.

Highly recommend checking out if you are trying to solve host display problems like these.