as someone who has a similar setup of sudo needing reauth after a while, i can tell you that it’s really no issue. keep in mind it only prompts you for a password when using sudo, meaning it prompts you when you run sudo su, and then su is just running. for as long as su keeps running, you don’t need to rerun sudo su, meaning you don’t need to reauthenticate.

in other words. the reauthentication requirement will never kill any running processes. it just requires a password when running sudo.

edit: also, i would recommend sudo su - instead, because it makes sure you get the env vars that root uses. running sudo su has lead to lots of head scratching personally. (especially on debian where /sbin binaries are not in the path when using su without the dash)