Why is it that in sololearn some users are in very high levels but when you challenge them the winner gets only 1xp.

Answer 1

That may be because eventhough if that person is in a very high level, the person might have lost many times compared to the wins in that particular challenge and the person might be expert in other course in which he/she has won many times which has boosted the person’s level.
The same happens to me when I challenge to other players.

Answer 2

Cause even if you're smart, SoloLearn challenges don't give people like me enough time to think rationaly