They have torrent downloads for a lot of content, I've downloaded almost a terabyte from them via torrent, they're just not bundled, as in you would need to retrieve each torrent file for each item individually, which might still get you a 429 if you automated it idk.

I've never actually got a 429 using a browser though personally, they do throttle aggressively though

Why sell? I thought the idea of donating to them is to make the information available for everyone for free.