Fitrah
In my opinion it’s not a real analogy. People die out of hunger all the time, but how many do we know that even attempt to eat grass? Their digestive systems won’t even accept grass, let alone curbing their hunger. As for Trinity, the real problem is not of firat, but in fact it’s a lie upon God. If God was 3 in 1, He is the one who would have told us that. How can we as humans figure out this information on our own?