Hitler was doing far too good a job making the Germans lose the war faster than they would have done if someone with a less dogmatic strategic mind was in charge.
An SOE plan to assassinate Hitler, called Operation Foxley was abandoned for this very reason....
He wasn’t losing the war any faster than Mussolini, who went into WW II with tanks that needed sandbags and a lot of inferior equipment [and generals and admirals]. And since Germany was the principal British opponent [by ‘43 Mussolini was a sock puppet], going after Benny instead of Adolf makes no sense, assuming an assassination attempt was going to made.