I tried out iGlasses to reduce the amount of background shown in my iMac Pro camera, but didn’t wind up buying it.
It and some others are mentioned here:
I use Webcam Settings with my webcams and it generally works well, even though it’s not updated very often (the latest update was about a year ago). I’m hoping it continues to work once macOS Monterey is released (or that it gets a compatibility update).
I’ve also experimented with Manual Camera. It doesn’t work as well as I’d like with one of my webcams, but may be a good choice in your case. I gets more frequent updates than Webcam Settings.
To add to what @johnalt wrote, I’ve used iGlasses in the past. Last I checked, it doesn’t provide hardware control of the webcam, it just processes the feed from the webcam. This can still be useful, but not having hardware control is limiting and the processing that iGlasses performs adds CPU overhead.
If you haven’t already, you may also want to check to see if LG offers software for the built-in webcam.