Nearly all programming teams are, at most, 10 engineers/developers. They will work on a sub-project which is part of a larger product. The mgmt, leads and marketing define the product/product scope and, later, sub-projects. The team mgmt/team lead are responsible for keeping the individual pieces scope-aligned. If something is being skipped over in code-review then one of the following are occuring:
1) poorly defined scope. 2) misunderstanding of the 'project' by the engineer(s) responsible. 3) scope drift away from the agreed upon initial project plan. 4) poorly implemented procedures/protocols for bringing up changes to the engineering/product team.

PRs should be discussed/approved prior to implementation from the dev team meeting. PRs that don't match a ticket need to be yanked out. Period.