Changing my username wouldn't solve this issue. I've PMed theymos (once in mid 2024, once 5 days ago) and I've waited a couple business days since I understand we all have lives. It's about post history and account status too if possible. After realizing everything I did improve privacy to the best I could during mid 2024.
In my experience: theymos probably reads it and responds when it's needed, but PMs are often ignored. So if you didn't get a reply, you can assume you're being ignored on purpose.
Judging by your topic history: if this is related to PMs you sent, I don't think Admin is going to help you as that would mean censoring PMs received by others.