I don't think this is correct. I just tried it and instead of the above I got a 60s lockout after about 20 tries, which then increased to 300s after the next wrong attempt.
(I don't know the exact number because, after failing to get the 30 second lockout in my first 5 attempts, I stopped counting.)
Unfortunately, I couldn't find any sources for GOS, pixel or android in general that would give a number, let alone the progression of lockout times.
Would be great if the number of allowed attempts could be changed in the settings, 20 seems like it would give someone who saw you enter your pin a decent chance.