What comms app do you use that actually makes use of the 4K+ camera? Most of the Zoom/Teams/Webex calls I see are in 720p, with 1080p in some rare occassions. If you want to look good on cam lighting is way more important and in a well-lit environment a basic 720p camera is sufficient. Those cheap sensors do poorly in low light and that's why you get noisy images with low frame rate as the camera is struggling to get good exposure.

For the fiber internet that really depends on how the company's systems are set up. If you regularly need to upload and download large files, then fiber is a godsend. If you're developing over VDI or SSH with everything on the remote server, then fiber won't give you an advantage provided you have decent cable or VDSL. Rather what matters is that you have a stable and preferably wired connection.