Whiteboard with your coworkers and architect what you are building once you have a pretty good grasp on how you want to solve a task. You probably have some code at this stage to feel pretty confident that it will work.
Agree on naming of concepts and design at this point, allowing you to change direction without reworking too much. Of course further changes to design will occur as you learn more during implementation. If they are major run them by your team again to keep them in the loop.
It is probably true that you could work faster, at least for a while, if reviews were more slack. That the company chooses to prioritize less risk instead.
Maybe it is just time to move to the next job since your learning curve is flattening?