https://wccftech.com/blizzard-severe-wow-classic-queues/

Blizzard is expecting extended queues on select WoW Classic realms due to extremely high demand and is already opening new servers.

Name reservation for World of Warcraft Classic kicked off earlier this week and various US/EU realms already showing up as full which will likely result in severe queues once the vanilla server option officially launches later this month. According to Blizzard, players with characters on the US Faerlina, Herod and Whitemane realms will probably experience extended queues, and as such, the new Stalagg PvP realm has been created.