Mechanic Explanation - Conflicting information - Sacred Flame + Elemental Weakness + Rakiata's Flow

From what i understood, in case of scared flame you would do less dmg with RF. Outside of the SF area RF inverts let's say 75 res to - 75, with SF it would invert for example 30 res to - 30. So you would deal more dmg outside of the SF area

Dont mix rf and ele week, because you low/negative enemy res,so rf reverse it.

Elemental Weakness is applied first. So if you reduce a monsters resistances to (-), Rakiata's Flow actually nerfs your damage.
Sacred Flame + Rakiata's Flow negates Rakiata's, because it sets resistances to zero, and the inverse of zero...is zero.

Sacred flame with RF should work since it says elemental dmg is based on the lowest elemental resistance. With the reversal of the resistances cuz of RF it would the former highest making it optimal. Elemental weakness should work in the same process but there I am not fully sure since I never run that combo. But instead of lowering the resistances it would be added to the negative value cuz of RF reversal