Is it possible to try to glide at, say, 100km?

Obviously the atmosphere is extremely thin at that height, but on the other hand astronaut would have extremely high speed at this moment which would help both gliding and add centrifugal force.

If gliding is possible at such height, then it can help lowering into thicker atmosphere prematurely, and therefore would prevent extremely fast deceleration.

Basically the more astronaut slows down - the lower it would glide, always trying to maintain manageable deceleration.

Obviously gliding idea was discussed by space engineers, but I couldn't find the reason why it was rejected.