It’s easy to say you’re good at rowing. Not many people know the difference, and if your score is fast enough on the Concept2 no one will question it.
I’ve also seen some pretty horrific back squat technique from people who can put up big weight, though. What it takes to improve is no more or less than any other movement to which you give credence. What it takes is leaving your ego at the door and committing to learning.
Do the best you can with what you’ve got. No one can blame you for that. As with your snatch which you spend countless time drilling with an empty barbell so too should you be spending time at a damper setting 1 on the Concept2 erg drilling phases of the movement and learning how to connect really well with a Concept2 if that’s what you use.