With introduction of Teams environments (aka project Oakdale), users can create environments and name them with special characters easily (because they can copy/paste them).
Currently power platform admin can delete environments on admin portal by re-typing display name and clipboard is disabled. I recently had a challenge to delete an environment, which had a special character (en dash for my case) in display name. The challenge is even broader when admin works with a standard PC, as special characters can only be typed using Unicode with a numeric keyboard (which does not exist on a standard laptop).
Ideally, admin portal environment design should be changed for smoother (for instance, add multiple "are you sure? Y/N" prompts instead of forcing admin to retype the display name)