The Umbwe Route might be short, but that doesn’t make the route any easier. Rather the opposite as you will need to conquer almost the same altitude difference on any route without good opportunities for proper acclimatization.
As a result, one of the major disadvantages of the Umbwe Route has the lowest summit success rates of all routes.
The challenge is not only in the altitude but also in the physical challenge as the route includes steep climbs right from day one.
Unless you are a very fit or an experience altitude climber, it will be a real challenge to handle this path.