I would say if you are using the Daniel Gatis developed background remover then you don't need a Gimp plugin. If you want it for videos, this works for me. Convert video to PNGs using ffmpeg. Then use a bash script to remove their backgrounds with rembg via anaconda. There are lots of background removers on github. Some use an online server but I want to do it locally not upload and d'load thousands of images. Also get a clear image stream with a neutral background like on a beach. Or in the sky. The AI is not that smart 
I experimented with just removing a green screen from video clips. There are probably thousands of free to use online. This is easy to do in kdenlive but that app only makes videos
Its PNG export is just huge bloat.
Now I found a video editor where I can import a thousand PNGs, remove their backgrounds and then export them as PNGs. It's not FOSS so I won't post it's name here.
I experimented with just removing a green screen from video clips. There are probably thousands of free to use online. This is easy to do in kdenlive but that app only makes videos
Its PNG export is just huge bloat.Now I found a video editor where I can import a thousand PNGs, remove their backgrounds and then export them as PNGs. It's not FOSS so I won't post it's name here.