Urgh. Having done every single set dungeon for the achievements a couple of years ago, the Might of the Earth was the very last one I did, so I hear that. However, just in case you’re not aware of this, for the Season Journey tasks (completing and mastering a set dungeon) you can complete the dungeon for any set, i.e. you don’t have to do the one from the set that Haedrig’s Gifts gave you. You also don’t need to do the dungeon solo. As long as you complete the set-specific tasks, the other person can help you, e.g. with the “kill all mobs” task.
If you ever did want to try (and I understand if you don’t from having read your posts) I would suggest getting six pieces of the Immortal King set armour and the Bul Kathos mighty weapons. Then use a fairly standard Whirlwind/Rend build, but swap one of the shouts out for Call of the Ancients. The set dungeon for IK requires that you kill all the mobs in there, and all the elites with Call of the Ancients and Wrath of the Berserker active. The IK set means that COTA lasts forever (so that’s trivial) and also reduces the cooldown of skills every time you spend Fury. As you’re constantly Whirlwinding (which spends Fury) you can refresh WOTB way before it comes off cooldown. Essentially, getting mastery of that dungeon becomes “hold down WW and kill everything whilst pressing WOTB every 15 seconds or so” and takes under 90 seconds.
I see from your Battlenet ID that you play on EU servers. So do I, so if you’d like me to take you through some higher content drop me a Friends request (Meteorblade#2266) and I’d be happy to do so.