I finally figured out how to stop fullscreen windows from moving to the first space when I open a new program in fullscreen mode (System Preferences -> Mission Control -> uncheck "Automatically rearrange spaces based on most recent use"). But now when I open a new window in the same program (e.g when opening a new Chrome window, the new window opens in the last space rather than in a new space next to the current window).
How can I make new fullscreen windows open next to the current window, just to the right of it?
Best Answer
The option you are disabling (Systems Prefs -> Mission Control -> Automatically Rearrange Spaces based on most recent Use) is what gives you your requested functionality. With this enabled, if you open a new "full-Screen" app, it will create the space (right) adjacent to the one you are working in.
It functions in the same way "alt/cmd + tab" works. Your most recently visited application/focused window will always be the (right) adjacent option.
It is possible that there is 3rd-Party "Mission Control-esq" apps out there that may give you your requested functionality, but I don't believe its possible with stock macOS