Should your life partner be less/more educated than yourself?

Whichever answer you come up with will be sub-optimal for your partner. The only way it might work on that basis is that if you have opposite criteria.

It might be better to have a broader range of criteria.

You're asking the wrong question.

Your life partner should be someone you trust and admire and who feels that way about you. Any other criterion is a recipe for disappointment.

It doesn't matter either way.