Remember wifi mesh is to extend coverage right? If you place a second unit in your room and your first unit is outside, likely the wifi signal is already degraded due to the walls and thus your speed will be slower.
Ideally, wifi mesh units should see each other in a line of sight, or be placed nearer to each other where the signal is still optimal.
Unless you are sure the signal in your room is optimal, if not it won't work as expected.
What you need is an access point, provided you have an ethernet jack in your room to provide you a connection for an access point.
If you die die want wifi mesh, then you have to place it outside your room where it communicates better to the first unit so that the 2nd unit actually extends wifi coverage.