From looking at it a few weeks ago, months after launch, their hastily launched extra region now faces the opposite 'dead servers' problem and merges aren't even in the cards for the time being. I quit because of it like 2 weeks in, so I don't know how long it took to get better. They did what they could to alleviate the issues given the rigid restrictions they worked with, but it was a shit-show for weeks. Tough luck if you had your character there, your character or server-bound purchased assets there, and so on. To give a negative example, Lost Ark is using very hard-coded server/region structures that were very problematic during the launch weeks, to the point that many EU servers could not be joined for hours because they were full. Just two examples from games that started on the then more plausible server model but innovated beyond that during their lifetime.

GW2 actually moved to a 'mega-server' tech years ago where that server just generates extra copies of a zone when it overpopulates, and barring some restrictions because a copy is full, players can move between them at will to join friends or events. It's mostly used for quest progression, but it could easily be used to separate that million players into managable sizes that basically use 'virtual servers' instead of hard-coding it all like they did when the made the game 20 years ago. WoW can transport you into separated versions of the close area or zone based on various states.

Character server transfer cabal ph