While I hope that options for 5e supplements make their way in, I sincerely doubt (and hope) options from the Dungeon Master's Guide do not. The options in the DMG are there purely as example or for NPCs. An example is the anti-paladin in the DMG, which has an ability that buffs all undead and fiends around them. This would mean as a player, if you fight fiends and undead at all you are instantly buffing your enemy.
Instead of wanting the DMG death domain, you're better off looking at the Grave domain in Xanathar's guide to everything. However due to the sheer amount of cleric domains in the PHB, I would be (pleasantly) surprised if it were to make its way into BG3.
