Just because it’s relevent... although steam officially states that the account name is unchangeable; if you contact support with a good reason and get the right person they can and do change your account name to another free one of your choice.
I have uh personal reasons for having done this and I know of others who have as well.
I’m not sure why they don’t roll it out more wisely - though I can say it did cause a couple of bugs until I signed out and back in on every steam device.
Each steam account does have atleast 3 internal unchangable account numbers that are exposed through APIs for developers to integrate with and use for things such as enforcing bans etc.
