If you change the Resolution(main stream) in the Record > Camera menu, the FPS is automatically changed. However, this does not match the actual max FPS, and it only changes to one specific FPS no matter what resolution you change.

ex) Maximum FPS automatically applied when all channels are changed to the lowest resolution(Lite options are off)

Maximum FPS automatically applied when changing to the highest resolution (same results as above)

When you enter the menu again after saving as above, the unsupported FPS is changed to 1.

*For second stream, the selectable FPS remains the same even if the resolution is changed. So, likewise, you can choose an unsupported FPS.