He didn't have to send Rose and Fin, he could have broke off after disabling the fleet killer's defenses.
It doesn't frame him as incompetent, it shows that he's reckless. There's a difference.
If it did that there wouldn't be a movie
Destroying the base makes it so the resistance A. Cannot return in any significant manor, B. Destroys countless pieces of equipment, and C. There was still people there when they fired, so it would have taken them out if it was a second sooner.
Turns out when you shoot a ship it explodes, who would have thought.
This is a genuine issue however
I'd disagree that he was, though due to his mistakes he develops then most as a character.