Here's what you need to know about streaming games. You need a CPU fast enough to run the game at the framerate and settings that you want AND the CPU has to be powerful enough to have extra power to also run the streaming software.
So if you buy a 4 core/4 thread mobile computer, you will need to limit your choice of games to games which require much less than that to run well. No Fortnite or PUBG in other words.