(Expanding from my comment)
I think this might be a conflation of a couple of books from the Pendragon series by D.J. Machale. Books came out between 2002 and 2009. They're about a boy named Bobby Pendragon who travels to various territories (realities). The main one you're mentioning would be The Reality Bug.
From the Wikipedia summary:
Aja explains that Lifelight is a virtual reality world—a computer that
gives people's desires the appearance of being real. Almost everyone
on Veelox is in it, living out their own perfect virtual lives. ...
Aja then explains that, because Lifelight is so perfect, hardly anyone
leaves. No food is being made. The territory is dying.
The contest book would be The Quillan Games:
The story takes place on a territory called Quillan, in the city of
Rune, whose population live dreary lives under the rule of the
megacorporation 'Blok'. Many people gamble on the eponymous games in
hope of a better life; but may lose their lives, their families, or
their professions if the bet fails. The games' celebrity players are
called 'challengers', and often kill each other during the
competition. ... Upon arrival on Quillan, Bobby witnesses a fellow
Traveler die in the games; but is soon captured by the android 'dados'
of Quillan's police force, and recruited as a 'challenger' by the
siblings LaBerge and Veego. ... Ultimately, Bobby wins the game and
the support of the people, who revolt against Blok.
The tribal house healing book might be The Rivers of Zadaa, though it could also be a scene from a different book I've forgotten.
This story takes place mainly on a territory called Zadaa. There will
be two main tribes here: The Rokador and the Batu. The Rokador live in
tunnels underground and are fair-skinned, while the Batu are
dark-skinned and live in a sunbathed city called Xhaxhu in the desert.
... Soon afterwards, Saint Dane, who is disguised as a Batu warrior,
beats Bobby up with a wooden staff. Bobby is almost killed but is
rescued by Pelle a Zinj, the kind prince, and recovers quickly in a
I can't find a mention of the planet in The Reality Bug having more than one sun, but a different territory in the series does. Snippet below from the first book, The Merchant of Death:
But it wasn't going to happen today. The suns were going down and it
was getting dark. Yeah, that's right. Suns. Plural. Remember when I
told you there were three suns? Well, they all set at the same time,
but in opposite parts of the sky.