Seconded. It may be that you're in a toxic environment. In such places it doesn't matter how good your design is or how tight you're implementation, you still get hostility and nit picking on code review. And not in a constructive way. Sometimes it's not you, it's them. When development turns into a dick swinging competition, walk away. It's better for your health.
Sometimes it's this attitude that is toxic to profitability. OP didn't say it felt unfair, and it's not right for this community to constantly reinforce the "big bad wolf" theory of senior engineer dick swingery when someone honestly wants to get better.
It's a play on words. The great grandparent suggested hiring a coach, i.e. a mentor or instructor, to improve his skills. The word coach, shortened from stagecoach, also refers to an intercity bus (what I would have called a highway bus as a kid). So, the reply is suggesting taking the bus to another city where jargon like "velocity" is not used. It suggests the problem is the company culture rather than the individual. I thought it was quite clever.