Evaluating private debt investments

Thinking about investing part of my capital in a fund that manages short term commercial mortgages (think bridge loans). These are all private loans. I have access to their holdings and performance has been good over 15 years but would still like to do some due diligence before investing - if only to satisfy intellectual curiosity. What would be some good resources and/or tips you could send my way to help me think about private debt and any of the tail risk involved? Thank you!