I'm sorry but everything I've found on here about this confuses me, so I have to ask, myself.

I just made a steam account, then added VRChat to my steam library, and clicked play on it. Then steam made an automatic VRChat account for me. I don't want it. I already have a VRChat account through VRChat.

I want to logout of the VRChat account made by steam, within steam. Can I only do this once I've started VRChat and it automatically logs me in?

Then I want steam to log me in automatically, instead, to my real, current VRChat account every time.

When you reply, please explain where to go and what to do step by step, specifically. Thanks.

Open your settings.
There's a button that says logout.
You logout with it.
Then you login using your VRchat account.
In the future it will log you in using said account to my knowledge.

Yes it worked! From what I could find from searching through help stuff, mostly what I saw was stuff about linking the steam and VRchat accounts, but the VRchat information said that that would be permanent, and that wasn't really what I wanted to do anyway.

Then I saw somewhere where they said to log out of VRchat when you had it running on steam, from the menu you get when you hit ESC, then choose settings and logout. I didn't think that would work. I thought I would have had to have logged out through a menu in steam or something. Thanks so much!