"Huge flue and triple wall stainless pipe (10”?) with no elbows."
Your open fireplace may not be efficient, but an insulated stainless steel liner? That's the absolute best thing to have, in my opinion.
Unlike a masonry chimney, which may never get up to a proper heat level that will keep creosote from forming because the stone/brick is a HUGE heat sink, an insulated (and triple wall construction gives it great insulating power) metal liner tends to get to, and stay at, proper heat levels (or even far above if you're a bonfire kind of guy).
The fact that you're burning well seasoned hardwood? Bonus.
And Locust? Excellent hardwood for fires. Burns long and hot and leaves an incredible bed of coals.
Now, that said, you really should have your chimney camera inspected every couple of years to make sure none of the joints have separated or that it hasn't developed a spontaneous split. Rare, but possible if there's an inherent flaw in the metal.