Webcam not working

Hello everybody,

My webcam is currently not working on my Dell XPS 15 7590. When I run the camera app I get the error code: 0xA00F4271   (0x80070018). 

I'm not sure when this exactly happened, but I think it might be at the same time that I had to install Ubuntu 20.04 as a dual boot on my laptop for a university course. I had to change some stuff in BIOS and in regedit to get that working (although it failed the first time and I had to factory reset). Now since I don't need that anymore, I decided to factory reset my laptop again (via SupportAssist) in the hope of just starting with a "brand-new" laptop. I've tried many things to get the camera to work, but none of them worked. Here a list of the options I tried:

• Factory reset
• Updating windows 10
• Upgrading to windows 11
• Enable camera in settings
• Enable camera in BIOS
• In Device Manager, I don't see an integrated webcam, only Sonix Technology Co., Ltd.
• Scanning for hardware changes/adding legacy driver in Device Manager
• Hardware scan in SupportAssist for Camera gives: Camera-Test Cannot Run
• Searching for driver updates 
• Disabling BitLocker
• Adding EnableFrameServerMode (value 0) in regedit under HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows Media Foundation

I think that's about all the options I tried and I've spent way too much time already on all this stuff. I really need to get my camera working for my online oral exams next month. Is there anyone who can help?

Thanks in advance!