TLDR: Does anyone know what hardware is necessary to force Sunshine to stream to a Steam Deck at 1280 x 800 @ 90FPS? Can any monitor be forced to support this if it supports higher resolutions and FPS or will a dummy HDMI dongle work?

So I’ve been trying to get Sunshine and Moonlight streaming working on my Deck. I’ve got them working at 60 FPS, but what I’ve seen indicates 90FPS will be harder and is a deck specific use case. I’m posting here as I imagine this will be a common question in a couple of days even though it primarily focuses on Sunshine/monitor hardware as opposed to the Steam Deck itself.

I’ve worked through Sunshine’s Documentation on my Desktop and can get it to change the resolution when streaming to my laptop to QHD+, but the issue I ran into is that my TV (CX Oled) doesn’t show 1280 x 800 @ 90FPS as a supported output resolution.

Does anyone know if there is a way to force any generic TV to support that resolution for streaming, will it depend on the monitor, or if I’m missing something obvious with this setup that makes special monitor configuration not necessary?

I’ve also been looking at getting an HDMI dummy receiver and configuring Sunshine to use that as I’v read that they can be configured to any output, but I haven’t tried one myself yet and none of the listing indicate that functionality which I would imagine they would if they could. Does anyone know if that is possible?