Can I use my keyboard & mouse with game pass on PC?

If the game had native keyboard and mouse support you may be able to use your PCs keyboard and mouse. You can use the keyboard for the actual xbox homescreen though.

Online gaming would become unbalanced. Not everyone on console wants to game with keyboard and mouse. Most on PC do so for the most part its balanced but only by how good the mouse/keyboards you buy so can be uneven. If you choose to use controller on PC
your at a disadvantage. Everyone with controller on console exactly even for online.

Not to mention i have to bring a keyboard and mouse to my loungroom to be competitive.

The Xbox can't be controlled by keyboard and mouse through the Stream mode at all. While it's possible in the Minecraft Bedrock Edition to use Keyboard and mouse, all other games don't accept keyboard and mouse input at all.

You might have to try Minecraft, if you can control it via Keyboard and mouse while streaming to your PC.

Absolutely, Kevin. It means that there is no issue with the game itself. It can be with the PC driver for mouse or keyboard or the mouse or keyboard itself that is the issue.

Pfff, people complaining about others using a mouse and keyboard probablys suck at the game they're playing and just want to shift the blame to those using a keyboard and mouse.

Personally, i enjoy PC shooters like Z-doom where i use a mouse and keyboard, it's pretty fun, but $150/£75 for a keyboard and mouse? I'd rather not.