I can't tell you exactly how brute-force resistant pixel+GOS is but I believe that it is very likely the best choice in android space.
Newer pixels (like newer iPhones) store the decryption keys to the flash storage on a secure element which (to my knowledge) is impossible to extract data from.
One area where the iPhone have an edge over pixel+GOS is that iPhones have the option to auto wipe the secure element after 10 failed password/code attempts.
But if you use a long (+14 characters) and complex alphanumeric screen lock password you've come a long way.
Also, I read somewhere in here that the owner profile is newer at rest and encrypted while the phone is off. Therefore you shouldn't use the owner profile for anything sensitive but rather put it in a secondary profile and power button > end session when you don't use it.
The TLDR is that I think you (or any other person for that matter) will very likely be the weakest link in the security model. I.e. social engineering, mis-configuration of the phone, tortured to give up the password, etc.
Hope that helps.