reviewdog provides a way to post review comments to code hosting service, such as GitHub, automatically by integrating with any linter tools with ease. It uses an output of lint tools and posts them as a comment if findings are in diff of patches to review.
Here is an introduction of reviewdog at https://github.com/reviewdog/reviewdog.
There is an article titled as "Automated Code Review on GitHub Actions with reviewdog for any languages/tools". https://medium.com/@haya14busa/automated-code-review-on-github-actions-with-reviewdog-for-any-languages-tools-20285e04448e
I think we can make reviewdog to annotate code review to newly uploaded PRs.