yeah you are right and I take the point, to keep the submission process as simple as possible within the current scope, the PR template will do most of the heavy lifting.
To address the UX concern, i can look at automating the entry creation through a github action that runs when the author opens a PR, the author only provides their repository URL and commit hash in the PR description in plain text, no JSON editing required, then the Action reads those two values, formats the approved-plugins.json entry automatically, and commits it to the PR, now that keeps the submission down to two inputs and a PR open, which is much closer to a single command experience. This keeps the complexity inside CI rather than requiring a separate tool like CLI helper
A CLI helper that automates this further can be added after the pipeline is running but adding it within GSoC scope would stretch the timeline beyond what is already planned, i am open to discussion on this devs UX , can you share your thoughts on this?