Software engineering isn’t like that. Not only are the tools changing every year, but 95% of the work in a project isn’t actually design or construction, it’s figuring out what the client wants or the product should be! Requirements are discovered as construction happens because most of the time software is solving a business problem not a physics problem.
There’s no certification because there isn’t something to standardize. Every company has different problems, technical solutions are always changing. Interview processes are trying to look at generic problem solving + communication + ability to translate some easy algorithmic idea into code. They don’t do a great job of assessing that, but the point is that two CS degrees can look identical on paper but there’s so much fuzzy interpersonal/business/requirement-assessment work that basically isnt captured at all by a degree, and is really hard to demonstrate on a resume.
I expect you would have a hard time getting top students to join your union.
(On the other hand, I don't care at all about side projects or seeing code on GitHub. I want to see how you solve a realistic problem that I have seen dozens of other people take a crack at for comparison.)