In Thor: Ragnarok, the Grandmaster says
"Time works real different around these parts. On any other world I would be millions of years old but here on Sakaar..." So GM confirms that time is doing something unusual on Sakaar, though he doesn't say what.
Also, we see that by the time Thor arrives on Sakaar,
Loki has already been there some (three?) weeks, even though he was thrown out of the Bifrost no more than ~30 seconds before Thor was. If three weeks can pass for Loki on Sakaar when only ~30 seconds pass for Thor in the Bifrost before he is also thrown from it, that suggests that time moves about 60,000 faster on Sakaar. Is this what is "real different" about how time works, or is there something else? Additionally, if Hulk has been missing for 2 years on Earth, does that mean he has been on Sakaar for around 100,000 years?
Are there any supplementary materials such as tie-in comics or any of the stories that were adapted for the movie that suggest that might explain this?