When using OBS/Streamlabs OBS, why can I not record in 1920x1080 when input source is 2560x1440?

● In OBS
1. Run OBS, click ‘Settings’

2. Choose ‘Output’ at left pane, and set the following options:
Output Mode → Advanced
Encoder → NVENC H.264 (if NVIDIA graphics card plugged)
Rescale Output → check and select “1920x1080”
Click ‘Apply’ and ‘OK’

In Streamlabs OBS
1. Run Streamlabs OBS, click Settings

2. Choose ‘Video’ at left pane, and set the following options:
Base (Canvas) Resolution → input 2560x1440
Output (Scale) Resolution → input 2560x1440

3. Choose ‘Output’ at left pane, and set the following options:
Output Mode → Advanced
Encoder → NVENC (if NVIDIA graphics card plugged)

Scroll down to Recording, check ‘Rescale Output’,

Select “1920x1080” (Output Resolution box)
Click Done