Our FAQ section at https://grapheneos.org/faq#encryption has documentation on the less aggressive older delay ramp up by the secure element. It's implemented by the secure element, not the OS, and it does not currently provide any configuration. The secure element could theoretically provide configuration to the OS but it doesn't so it's not something which can be added by the OS alone. The previous delay ramp up was more than enough to protect data with a random 6 digit PIN but it's now more aggressive, likely to help with weaker lock methods. It's still not a good idea to use less than a random 6 digit PIN.
Entering a PIN below 4 digits or entering the same PIN twice in a row won't be counted as an attempt since it will reject the attempt before it tries to use it, avoiding counting towards a failed attempt. Ignoring an attempt with the same PIN twice in a row is ignored so that if someone slightly misremembers their PIN and keeps entering the wrong one, they aren't actually making additional unlock attempts.
This is all standard and we don't change anything about it. We have a bunch of related changes but not to these basic properties.