Game uses linked account's name

So I have linked my classic Battle.net account to the new one, and the game decided to use my old nickname instead of battletag for the multiplayer games on EU realm. The game now uses the nickname “khj” on EU and “khj#21487” on Asia and US.
And since I mostly play custom games with save/load systems that bind the progression in the game to the nickname, I can’t use my saves made on Europe server on other servers and vice versa. I would like to have the same nickname across all realms, preferably the battletag - to prevent issues in future - but couldn’t find any way to do that myself. Is there any way to do that?

did you find a solution to this?
i have the same problem

did u find a solution ?

Don’t think there is one, but its not even possible to link a classic account anymore as all that ever existed are expired unless you’ve been using them to play diablo II classic the entire time