> all the skills my employees will need can be learned on the job. > optimize the time it takes for an arbitrary hire to become independent

So you are looking for somebody in top 5% cognitive ability and top 5% independence which is what pretty much every other employer wants.

My advice is if you can pay competitive FAANG salaries (or compensate lower salaries by prestige/saving humanity/bringing people to Mars), just do what everyone else is doing - Leetcode, behavior interview and architecture interview. Innovate on something else, standard interview process will give you smart motivated folks.

If you can’t pay those salaries, you need to be creative and decide what compromises you are ready to make and tailor interview process to them. No one size fits all process here. You are essentially looking for people who failed in standard process while still posses qualities you need. Expect to spend more time on hiring and have more bad hires.