Thank you Alyta for trying to help out here!
And hi there friend! Sorry for the delay. I was looking into this and found the issue!
You were set to an "inactive" group, which cannot change their name. I have manually set you as "Daeva" now, so do let me know if you can change your name now. If not, send me a DM and I'll update it to your preference this one time, then you should be able to change it in the future!
Hope that helps!