Hello a random user,
Welcome to Microsoft Community.
After fully reading everything you've posted here, I've noticed that you've tried a few recovery actions, such as:
Disable the camera device in Device Manager and then enable it again.
Download and install the driver and firmware package for the Surface Pro 8.
Uninstall the camera driver, then restart, and let the Surface redeploy the camera driver.
I actually think what you've tried so far is quite correct, but let me give you an official diagnostic tool here:
Fix common Surface problems using the Surface app and Surface Diagnostic Toolkit - Microsoft Support
You can continue to diagnose the camera functionality of your Surface Pro 8 with the help of Surface Diagnostic Toolkit (SDT), and if SDT is able to give you some suggestions after the diagnostic is complete, then try to follow SDT's subsequent recommendations.
But if the SDT tool didn't help you either, and you're still looking to get some more tailored advice and have no intention of just sending it in for repair, please allow me to recommend that you contact the Surface Technical Support team.
I'll share the guidance process for contacting them here:
1. Use your personal Microsoft account (not your organization account) to access the following links:
Contact - Microsoft Support
2. Type Surface, press Enter, and click "Contact Support" at the bottom:
3. Select Technical Support and select the device model you are currently using in Produce family, then click Confrim:
4. You will see contact options for Chat support and Phone support, please contact them during working hours to suggest contact:
I wish you all the best.
Best Regards,
Mitchell | Microsoft Community Support Specialist