had a stupid idea: a dwarf paladin with the durable feat, defensive fighting style, tough feat, max con (20), plate armour, a +1 shield and the spell shield of faith. I ended up rolling it and got this: 61 hp, 24 AC, advantage on death saving throws and can heal 1 hit die per turn (1d10). Note this is at 5th level at 20th level (I'm going to give specific magic items) with a +3 shield, +3 plate armour, a ring of protection, a +3 maul, gauntlets of ogre strength and the boon of fortitude give you a paladin with 20d10 extra hp in reserve, advantage to death saving throws, 325 hp and 30 AC that can attack twice a turn each doing 2d8 radiant + 2d6 bludgeoning +3 bludgeoning +4 bludgeoning. and +10 to the attack roll. (2d8 radiant is from divine smite) honestly if the dm managed to kill this thing (like fully dead either overkilling so much it bypasses death saving throws or the paladin failing all three) that is insane on their part.