I had the same thoughts about using a domain as username and it is basically smoke and mirrors. I did not know however that you can use a domain for a bridged account. Are you saying that my ActivityPub account that is bridged to Bluesky can have a username that is a domain that I own?
Perfect timing for me! I was starting to plan out how I was going to transcode my media library and had decided to write a script to do it. So I’ll give this one a try!