Help me make the ultimate 5e survivalist.

[KorvinStarmast]

If you get to 14, a zealot barbarian becomes immune to death from HP damage while raging. They're pretty hard to kill.

I think this is going to stay at about level 10, per the OP. But I agree on the shield/spear PAM. My Orc Battlemaster did that, and he was very durable.

Celestial Warlocks get a pool of healing, and at higher levels, a self-raise 1/day.

At level 10, they give self Level Plus Cha Temp HP per long rest, and half of that to up to five party members.