Landmannalaugar to þórsmörk is one of the most famous hike in Iceland ( https://365project.org/yaorenliu/365/2023-08-21 and https://365project.org/yaorenliu/365/2023-08-13 ), therefore the crowd at Alftavatn Huts. The hut management seems have reputation of "making mistakes" of double booking. Imagine that you have to double up in one bunker - include the upper bunker - risk fall off it.
Lucky 4 members of our team camped out. The other group (they paid for the entire guided hike) were very cozy sharing the other half of the room 12 people, 6 beds.
Despite this, I would love to go back to hike the entire trek.