Someone who has a peculiar inside is a very curious soul that might be interested in unusual details or facts. Someone who has a rare ( almost bizarre knowledge) Life and existence are certainly extremely complex topic so plenty of room for “ peculiar inside”

Unique understanding is more commonly used. Peculiar Insight would be understood but it is more artistic and implies a unique - to the point of being bizarre - insight. Not a bad but unusual.

hey Shana, I love them both but if you'd like to sound posh - use the first one :) Take care and see you in my classes.

Both of them can make sense for me.