I'd like to know if there is an English equivalent to the Swedish idiom "gå över ån efter vatten", literally translated "crossing the river to get water" (i.e. solving a problem in a clumsy roundabout way when there obviously is a much easier solution).
It is a metaphor based on a Alexander the Great.
Hmm... I'm not at all sure that this has the required meaning.
Maybe this is what you mean? but maybe not.
As I understood it, the OP wants an idiom that means "solving a problem in a clumsy roundabout way when there obviously is a much easier solution". I feel sure there must be one! All I can think of is "beating around the bush" and "gilding the lily", neither of which are really right. (Oh, and "reinventing the wheel", which is also not exactly right.)
Before I know it, I'll be writing my own idiom dictionary here...
Maybe I grew up around a lot of Swedes and it's not really an English expression.