Can you negate the Frightened condition by not looking at the source of your fear?


As the title says, if you cause a creature to be Frightened of you, as in the Frightened condition, but they can somehow manage to not see you, do they stop rolling with disadvantage to attacks/ability checks?

Below are scenarios to illustrate my question.

Scenarios:

  • If a creature is frightened of you, and they turn their back against you to hit someone else, would they no longer have disadvantage to attack rolls/ability checks?

  • If a creature is frightened of you and they have Blindsight, can they close their eyes to stop seeing you, and hence stop rolling with disadvantage?

  • If a creature has 60 ft of movement and is frightened of you, and there is a corner they can reach in 15 ft that will block you from sight, can they run to that corner to stop being frightened, then run back to attack without disadvantage? Assume they would not provoke OA to do this, although the OA is immaterial to the question.