I've been known as 'Stack' or 'StackSmith' for decades. It's a convenient piece of bling - in my case, I am proudly wearing my Forth roots (even though technically, I've never really used proper Forth - I've been writing my own forths most of my life). But I digress.
gemini://lyk.so/gemlog/009-why-a-pseudonym.gmi
And other related posts about the use of a #pseudonym ...
It seems entirely reasonable to use a nickname of some sort for casual interactions or venting hot gas into the vacuum. It does not by itself imply bad faith - especially if it is obviously a made-up name. (I get a lot of phone calls trying to scam me, and usually the caller has a heavy Indian accent and claimes to be Jonathan Ashford Biddle, CEO of Chase Bank or somesuch... In proper context a [fake] name communicates quite a lot, I suppose)
When I actually interact with someone - perhaps to collaborate or further explore some idea, I generally introduce myself properly, just to clear the air.
Mr. StackSmith is my father (not true!). You may just call me Stack.