The discussion revolves around the need for admins to be able to change usernames, despite filters. per_coh uses a specific username format for staff users and wants to be able to bypass the reserved usernames filter to change usernames. pfaffman suggests that allowing admins to bypass filters could be problematic, but also proposes using group flair to identify staff members.
per_coh currently uses flairs but wants to explore other options to make staff users recognizable. RGJ shares a list of ways to make staff users more recognizable, while khenmu suggests taking inspiration from Blizzard’s approach. JimPas recommends adding a background color to staff posts using CSS to make them stand out. Overall, the discussion focuses on finding creative solutions to make staff users identifiable on the platform.
We use a certain username format for our staff users (_). To make sure “normal” users don’t look like staff in any way I’ve blocked certain characters under reserved usernames
Problem is, as an admin I can’t even circumvent the filter to change a username. When a new staff member joins I have to remove the filter, change their username and quickly re-enable the filter.
As an admin I’d like to not be blocked by that setting.
Yeah, that’s annoying, but I’m often annoyed that the tag requirements that I want enforced are not enforced for admins, so it could be just as annoying to change it to give admins license to break the rules that they have tried to impose on themselves. 
And from the Jay-always-treats-feature-as-support department, you can also use Automatically add group flair to members’ avatars which is much less subtle, so another way to solve your actual problem is to let the flair do the job of making it clear who is staff.
Maybe you have too many admins?
I use flairs too, but somehow there are always users who refuse to see, so I’m looking for everything I can get to help them.
Here’s a good list of “everything” Make staff users more recognizable with customized avatars, posts, and mentions
You mention staff users; is this for a company with a recognisable logo?
If so, you could always take a leaf out of Blizzard’s book.
Another way to make staff replies stand out is by adding a background color to their posts as per
Scroll down to Post #9 explaining where to make the change in the css.
Thanks for your thoughts, everyone.