The specific citation about the length of a cookie is a recommendation and not a law[0]. The key word is 'should'.
I'm not a lawyer nor claim the ability to interpret GDPR legally, but I have seen companies that actively worked to edge case GDPR to their advantage (I was part of one). We would have lawyers and other 'GDPR experts' tell us what was possible and what wasn't then simply extend into the grey area.
Here, I reject the Halon's Razor[1].
[0] https://gdpr.eu/cookies/#:~:text=All%20persistent%20cookies%....