The whiteboard standard already acts like a de facto license.
Algorithmic/data structure more theory-oriented problems are unrepresentative of "actual work" and are annoying, but what's more annoying is how the process is 1) opaque, and 2) repetitive. So you end up with candidates grinding through 80+ Leetcode problems to both master the skills necessary to ace these problems, as well as covering as many commonly-asked problems in a bid to game the system by preempting their interviewees questions. Goodhart's law abounds. This basically makes the process into an interview version of standardized testing. But- despite the standard prep process and a standard bank of questions, it can all easily fall apart because of subjective interviewer opinion, and so all the preparation is for naught. Candidates end up having to do the interview gauntlet for each company they apply at.
So standardize it. Put out clear, industry-standard rubrics for how one's performance is graded. Don't say "we only want to know how you think" and then ding candidates for not getting the right solution. You obviously care about the right answer as much as the thought process- don't be disingenuous about it. Maybe even standardize the level of difficulty of problems. And most of all:
Make this process a one-time thing.
Or rather, a once every five year thing. Outsource the ds/a interviewing section to a third party testing organization, like what Triplebyte is attempting to do, and have the actual interview be personalized to the company. Ask domain specific questions, relevant experience questions, system design, and culture fit questions during the company interview. And leave the DS/A portion be akin to the licensure tests that other engineering disciplines and STEM professions already have.
Software engineers may hate credentialism, but if it's a credential that you only need to take once or twice in a decade, then it's already far superior to the current system that forces candidates to undergo this each time they change jobs.