I have nearly 600GB of photos in it and regularly do Takeouts every year or so. It takes a while and the format isn't that great (it's a ton of separate zip files), but it does eventually work.
Unless I am mis remembering, it generated about 200 or more ZIP files that you have to download one by one.
You can set the max file size per ZIP file to 50GB instead of 2GB, then it will only generate 7 zip files
Thanks. It seems to be new that option. I am doing it right now.