Can someone please explain?

Long story short there was a guy on Twitter who ran a challenge and posted his seed phrase in chunks of 4 words. On the 2nd last day 20 out of 24 words were known.

If 20 out of 24 seed words are known, 4 would have needed to be brute forced. But considering seed words are generated using Bip-39. (Wallet was electrum). That would mean the last 4 words have 2048⁴ possible combinations. If I did the math right that would be almost 17.6 trillion combinations. How did someone manage to brute force that in like 12 hours? Wouldn’t you need to create all those wallets too? is there some crazy software out there that can do all that?

Here’s the tweet if you want to look into it:

https://x.com/vikrantnyc/status/1730943283059212477