Because no one has thought of it

Because they need to be in the moment to do it. Also Maul and Palpatine did it

They can, most of the time they just use a force enhanced jump to pull themselves up instead of pulling themselves like a grapple hook but they can do both.

While I don't particularly like this moment in TLJ, Leia shows that if you're focused you can do it

Generally it's easier to just Force Jump though; takes less mental energy and allows you to remain focused on whatever you're trying to maneuver towards or awa from

I don't know but hey it worked in Lego Star Wars: The Complete Saga

I look at it this way. When someone uses a force ability, It’s ultimately a “reach out” manipulation. The ability is center around the wielder. Therefore, perspective matters. Just as you can’t pick your own self up like a grappling hook, a Jedi can’t because the Jedi is the fulcrum and can’t project their powers to act remotely upon themselves.

^I don't know if this is true or not, but I like the explanation, it makes a lot of sense.