The short answer
You are the person who makes the deal real and keeps it honest — that's a defined, valuable job. The fix isn't to pick a side. It's to name what you actually do, set the terms of your role out loud, and stop letting others define your job for you by default.
You sit at the place where a promise gets made and where that promise has to actually work. Research on cross-functional sales roles shows this position is structurally real — it exists because neither pure sales nor pure engineering can close the gap alone. The tension you feel isn't a personal failing. It's what happens when a bridge role carries real weight but has no clear owner. Both sides pull on you because neither side fully claims you, and that leaves you absorbing friction that belongs to the org, not to you.
Marcus wrote about not letting yourself be yanked in opposite directions — not slack, not furious, not wandering. That's your situation exactly. The soul that gets pulled hard in two directions at once burns out fast. The steadiness he points to comes from knowing what your job actually is, and holding that line without apology. You are not a salesperson who knows tech. You are not an engineer who tolerates quotas. You are the person who translates between a real customer need and a real technical answer — and that role has its own integrity worth defending.
This week, write one paragraph — just for yourself — that defines your job in plain terms: what you are responsible for, what you are not, and where your honest judgment lives. Then find one moment in the next few days where you say out loud, in a meeting or a one-on-one, 'My job is to make sure what we promise is what we can deliver.' You don't have to fix the whole structure. Start by naming your ground.