The likely reason for higher resolutions not being listed as available is because Logitech Brio 4k supports only compressed video formats at resolutions higher than 1920x1080.
Support for compressed video formats when using MATLAB WEBCAM is currently not available, but is under consideration for a future MATLAB release.
Note that Image Acquisition Toolbox with the winvideo adaptor (on Windows) does support compressed video formats such as MJPEG, so this might be used a workaround if Image Acquisition Toolbox is available. However, note that Image Acquisition Toolbox does not currently (as of MATLAB R2018b) does not support H.264 format (which some camera models might use for high resolution video formats). To detect which resolution and video formats a camera supports you can use the detectDevices utility in MATLABROOT\toolbox\imaq\imaqextern\utilities\detectDevices\win64
More information about winvideo adaptor you can find here in the documentation:
