A Simple Quick Band Aid fix
Force a player to log out after 3 hours of gameplay. I.E they can't que for dungeons, raids, or progress in story. Also add priority for long time subscribers, 2000+ days of subscribed as well as legacy players given automatic priority. Ban people (including streamers) using third party tech to by pass the afk automatic log out timers. Also add a queue placement priority for players that are kicked due to timing out in queue or 2002 out of queue.
Honestly quick simple fixes that could be done on SE developer end and probably something streamers don't like, but honestly, everyone pays to play this game not just streamers.
boot afk accounts - not based solely on time...
Kick players who are not only inactive, but any that have not changed position for more than 30 minutes. There are people who use macros and automation to prevent the 30 minute AFK timeout.
Clear accounts and make more room for other players.
This would only be for a month or two until things settle down.
Unfortunately there are players who are using macros or other means to keep their character "active" so they can stay connected all day to avoid the Login Queue.