I'll also say you are barbarianing correctly.

I absolutely want my barbarian to soak damage so others don't take it. I'd rather be the on going down to 0hp then anybody else.

Like Man_over_game said, I'll reckless attack against someone who is going to hit me anyway (A recent fight with a fire giant, he had to roll a 4 or less to miss. Sine h was hitting me regularly with disadvantage it didn't matter in the slightest to give him advantage. Or if I really need to kill a weak enemy in one hit, in which case I'll use -5/+10 from GWM too.

I find those are my 2 big roles in the current party. Regular damage against big guys, and clearing up little guys.