@LXF Thank you for reaching out to us, regarding your ask related to troubleshooting PR request for your Sentinel solution.
Any issues with GitHub, needs to be posted on GitHub platform -
You can raise the requests via these options mentioned in the above link
https://www.youtube.com/watch?v=jRLGobWwA3Y
The Azure DevOps team and DevOps community are actively answering questions on a separate forum where you'll get the best answer:
https://developercommunity.visualstudio.com/spaces/21/index.html
Let me know if this information helps you in right direction, feel free to post back.