why would brute force do it so quickly?
if it is true brute force
and you have say 1500 word repeated 23 times.
There are hundreds of bots out there monitoring millions of easily hacked addresses waiting to sweep deposits the instant they show up. We've seen it countless times with brain wallets. Brain wallets generated from easy to guess phrases, such as common words, phrases, quotes, lyrics, etc., have any funds sent to the derived addresses stolen in under a second. These same bots are almost certainly also watching the addresses from any and all publicly revealed seed phrases, and any weak seed phrases, such as the same word repeated 23 times.
This is of course completely separate to a seed phrase including the same word twice or even three times, and these seed phrases are no easier to brute force than any other randomly generated seed phrases.But that is not brute force that is more like social engineering. Which would be a bit different. It is more like using
000
111
222
333
444
555
666
777
888
999
123. as your first attempts on a 3 digit combo in the hope the programmer was lazy
btw if it works why not.
I do agree don't use 1 word 23 times as someone could simply try 1 million seeds that appear common .