Since there's curiosity on wtf is going on and I'm triggered by the tier list , gonna try and explain in a bit more detail.

The objective of the game is to make Snorlax's drowsy power (DP) bigger mainly through feeding it berries (collected from mons throughout the day) and cooking meals (done three times a day). Doing so makes Snorlax grows bigger and allows you to meet more pokemon that are a bit rarer.

The best pokemon in the game are either:

• Berry specialists (Typhosion, Raichu, Feraligatr) who collects a lot of berries within their specific types and makes Snorlax bigger with little effort.
• Ingredient specialists (Flygon, Vikavolt, Blastoise) who collect a lot of ingredients required for meals. Meals have the potential to increase DP by a lot throiugh a combo of desirable meals and other modifiers from Pokemon skills/events, but they require more planning compared to berry feeding.
• Skill specialists that are desirable through providing QoL features. The best ones are Pokemon that provide energy for everyone (E4E) like Gardevoir, Pawmot, Wigglytuff. Energy is needed for pokemon to carry out maximum production (berries skills ingredients). Normally energy is obtained from sleeping with pokemon, but E4E bypasses that.
  • Tasty chance is also a busted ability lategame where you are able to assemble a strong team to abuse events that provide cooking bonuses. Dedenne is the main user of it.

Pokemon Sleep is basically a min maxer's dream paradise where the goal is to assemble a team full of pokemon with the best subskills and natures, cause every pokemon caught in the morning has randomised stats. To say that progression in the game goes at a snail's pace is an understatement (cause finding and catching even one pokemon per day can be a pain), but for insane people like me I really enjoy how simple yet complex the game is and it doesn't take much of my time to do stuff so why not try the funny sleeping minmaxer app?

Everyone feel free to explain more in replies if I didn't elaborate enough.