> Beliefs, almost by definition, don’t have much to do reasoning

There is nothing in the definition of a belief that precludes arriving at it via reasoning. In fact, one of the definitions in the wiktionary is:

2. Faith or trust in the reality of something; often based upon one's own reasoning, trust in a claim, desire of actuality, and/or evidence considered.

Merriam Webster:

3: conviction of the truth of some statement or the reality of some being or phenomenon especially when based on examination of evidence

Beliefs are hypotheses not testable on a reasonable timeframe.