Are you asking about a “second mastery”? Like what you could combine it with? You did write “second build”
If you wanna continue with 2H melee I’d say elementalist (shaman + demo), vindicator (shaman + inquisitor), conjurer (Shaman + Occultist) or even druid (shaman + arcanist) is better than Warder (Shaman + soldier)
Nevertheless, warder is still recommended by many (no idea why) and I made a beginner guide for it here ☄ Collection of malawiglenn's Beginner Friendly builds it is not completely up to date but is still 95% relevant to you.
Good luck