So the newest unearthed arcana brought us the armorer subclass, with heavy armor proficiency, and temporary hp as a bonus action.

Onto the build:

Warforged, for that sweet 1 ac and con boost Get the heaviest armor you can get, and a shield. Splint will get you 17 2 1 for 20 ac, plate gets you 21.

Infuse your armor, for yet another 1 ac, with 2 at 10th level. temporary hitpoints each round equal to artificer level lets you soak up what attacks do hit you.

con saves and racial poison resistance, disease immunity, and sleep immunity keep you on your feet from magical effects.

Mirror image is slightly weaker due to the lack of dexterity, but even with a half decent dex stat, non-concentration damage deflection solidifies your tankiness against monsters with extremely high to-hit bonuses, and to help deflect any nasty attacks with riders, like shadow strength drain.

Absorb elements, and eventually resistant armor, block high damage aoes like fireball, or a dragon's breath attack, and of course, the temp hp softens the hits as well.

Finally, take the heavy armor master. Combined with the temp hp, the damage reduction makes you nearly as tough as a raging barbarian.

And the icing on the cake is that you can dump strength, and to some extent dexterity to put all points in con and int to fortify you even further.

In the aggro department, you get thunder gauntlets, which shields your squishier allies from hits, and encourages monsters to attack you. extra attack lets you lock down two targets, or make certain one is locked down.

Wall of force partitions off enemies and provides immense battlefield control once you get to that level.