Thankfully, lumber has developed not-imprecise grading methods that are tied into guaranteed load values that are tied into architectural plans (which themselves include safety margins).

Basics: https://www.southernpine.com/grading-methods/ and https://bof.fire.ca.gov/media/llad34j2/full-14-b-presentatio...

Examples: https://www.nelma.org/the-grade-rule-book/ and https://nlga.org/wp-content/uploads/2023/01/NLGA-GR-2022-ver...