You really don't need a bunch of complicated infrastructure for this. I did this in the past by just creating my own high level feature branch and having PRs in

You really don't need a bunch of complicated infrastructure for this. I did this in the past by just creating my own high level feature branch and having PRs into said branch. This was all my own branch, but the purpose of the PRs was to get feedback before the whole thing was ready to be merged back to main. While the final PR will be large, everything has already been reviewed so you aren't losing anything in terms of review quality.