You have active output. That's why settings options disabled (inactive/grayed out).
To get what kind of output is currently active in OBS you may try to make custom script and run it. The script will print to the log-file of OBS all possible outputs and its current states.
See for details (the script itself and brief info how to use it):
I can not figure out what video output is still running thats perventing me from editing my video settings. Any help?https://obsproject.com/logs/40mfFX8faB2uu6Ke
obsproject.com