I don't think this can be correct. Takeout was released June 28, 2011. GDPR was passed April 14, 2016 and went into effect two years later.
I seem to be luckier than sibling comments; my gmail+photos tasks have been reliable. Three big differences from the author: I have closer to 40GB than 200GB of photos, I download the zips from Google rather than having it post 200GB+ to OneDrive, and I unzip my backups when they happen and move them to network storage, rather than rely on them to be 100% automated. I do recall one manual run failing and I was notified.
I do wish some pieces were a little more intuitive, for example how the Drive vs Docs/Sheets/Slides overlap is handled.
I know anti-Google sentiment is very high here, and disclosure that I worked there in the past, but IMO Takeout is a user-friendly effort and they're well ahead of other companies, big tech and especially smaller and non-tech, there. I might be selling Facebook short; they do have an exporter but I haven't used it. [Edit: of course my opinion would be different if I ran into broken exports like a couple sibling comments report.]