When you call the humans who keep production safe “the bottleneck” you’re painting a very specific picture. The reviewer as the obstacle. The gate as friction. Something to route around. Cue in the Balrog scene from Lord of the Rings. That picture determines what you build. The tools to remove reviewers look different from tools to support them.
writing lines has never been the bottleneck, that's only something a junior would say. The bottleneck is always requirements: changing, understanding them, making sure you don't miss test cases before writing any code.