How to have jenkins add a review to a pull request
I guess the simplest and direct solution would be to use GitHub API: https://docs.github.com/en/rest/reference/pulls#create-a-review-for-a-pull-request
But for the requirement you have, PR checks is usually the way to go and you have a plugin that does the API communication for you: https://www.jenkins.io/doc/pipeline/steps/pipeline-githubnotify-step/