If you have an issue with a more senior project engineer, directly give your resgnation notice and DO NOT give feedback and go by the books as it will be wasting time because it doesn't matter even if you bring angles to wetness the bullying, and feedback will be closed with nothing and irony here. The other person will know that you went to the HR and will continue the hersment in a way you can't prove it.
I mentioned that all my managers understood the psycatric letter and gave flexibility to use my breaks as I wish. However, other managers were complaining about this or using the helping apps on my phone. If the employee is doing all of the work they are assigned and by being productive, I think they should cut the nonsense and let them do their jobs.