Hey there Tresor18,
We'd like to help get the person you're calling to see your video as well during a FaceTime call on your Mac.
Great step already trying a restart of your Mac, along with confirming you have no issues using your iPhone. If we're not mistaken, great job on restarting your Wi-Fi router as well.
We see you have macOS 11.2 installed, but the latest is macOS 11.2.3. You can verify the version number installed by clicking on the Apple logo at the top left corner of the screen, then on ‘About This Mac’. Here's how to first Back up your Mac with Time Machine, and afterwards, here's How to update the software on your Mac.
If the issue remains, we recommend the steps under the sections 'If your camera or microphone doesn’t work' and 'If you need help with your connection or call quality' here: If FaceTime isn't working on your Mac
Take care!