Building a small internal marketing department something you could consider?
I've actually found myself really limited when it comes to agency work. Had a good one in the past, but that was for larger technical projects where I could trust them to handle things while I focused on the day-to-day. It was more about supporting a project and keeping my team's bandwidth manageable, not handing over the whole marketing function.
Did a short stint at an agency once and honestly, hated it. Some of the stuff they did felt unethical - always rounding up billable hours, pitting employees against each other by publishing everyone's weekly billing totals, pointing out who needed to bill more. The whole place felt like a toxic sweatshop. Barely any QA happening, and if something was messed up, you'd only hear about it if the client complained. Sounds a lot like what you're dealing with.
That's exactly why I left. Couldn't deliver the quality of work I'm used to as an internal team, and didn't feel comfortable putting my name on projects where the only direction was "do this, do that." Client meetings were usually just the consultants and account managers - rarely involved the people who actually did the work.
Not saying all agencies are like this, but the stories I keep hearing follow the same pattern. My feeling is you really need an internal team that believes in what they're selling and understands the product. Without that, marketing becomes a checklist. And that's probably all the agency sees it as too.