Focused Observant

General Feat, You gain the following benefits.

Ability Score Increase. Increase your Intelligence or Wisdom score by 1, to a maximum of 20.

Perceptive Strategist. You may use this ability if you have not used your speed to move or taken any other actions.
You can use the Search action (no roll required) and choose a target that you can clearly see.
As a result you get one of the 3 perks in the order provided you may not choose the order.

1. You are able to discern one vulnerability of the chosen target.
   - if the target does not have a vulnerability or is narratively impossible to discern one then-
2. You are able to discern any resistance of the chosen target.
   - if the target does not have a resistance or is narratively impossible to discern one then - 
3. Your next first attack or spell against the same chosen target has a +10 to hit (provided you can still see the target) and specific rules apply for rolling 1 and 20 .
   If you roll a Natural 1 on the next first attack or spell against the chosen target, treat it like 11 and not a complete failure.
   If you roll a Natural 20 on the next first attack or spell against the chosen target, you may max the damage output.
   
   Once you receive one of the perks above your turn is done.
   
   When you use this feat again, you may discern a different weakness or strength of the enemy targeted (if any).
   The bonus to hit is not stacking and is being overwritten.
   
   

The terms vulnerabilities/resistances is a direct connection to the target's stat block.
The idea for this feat is that the character has developed an ability to discern their opponents' natural strengths and weaknesses by focusing all their perception on them.
Any additional buffs or debuffs inposed by any other means to the target is up to the Game Master's discretion if they are to be revealed or not.