They ultimately realized that the fifth season simply had gotten too adult for Cartoon Network (and that dubbing it into many languages no longer made any sense), so instead the fifth season was ultimately given an HBO Max release in European markets years later. A late release for sure, but it's better than nothing.
On HBO Max in most European markets, the fifth season has dubs in German, French, Italian and Hungarian, as well as a Ukrainian voice-over exclusive to HBO Max.
Although the Romanian dubbing for the first four seasons of Samurai Jack is available on HBO Max (in addition to the preexisting German, French, Italian and Hungarian dubs, and the HBO Max–exclusive Ukrainian voice-over), unfortunately that's not the case with the Danish, Swedish, Norwegian, Dutch, Polish or Bulgarian dubs.