Thank you @nhl-pl . Will try and update.
SOLVED NodeBB Theme
Which nodebb theme has a display like discourse, with all the posts on the home page instead of the categories ?
@Gaurav-Grv-Robinson they are not special themes. you can get that with any NodeBB theme. it's just a setting in ACP.
All those sites are using /recent route as homepage instead of /categories
You can change it in ACP -> General -> Homepage
Oh, thanks a ton.