In my head canon I have a bit of a timeline made for how the Wario games (Land and Ware included), ignoring release dates and more putting in them in a different order.
First 3 Games would be:
Wario Land
Virtual Boy Wario Land
Wario Land 2
These 3 first titles tell the story of Wario's first 2 successful treasure hunts, and the stealing of his castle's treasures as he recovers it.
Then Wario World happens, as the castle is still seen, it is unknown which one of the endings is canon, but in my head canon an ending where he loses the castle is what happens next.
Attempting to become rich again, the events of Wario Land 3 happen, as he uses the only thing that remained from his glory days, the Wario Plane, to search for treasures, he then finds himself in an alternate world, which at start drains him of all his power to which he slowly starts regaining into improved and enhanced versions of his old moves (And would be using these in WL4, his powered up shoulder dash being an example).
As he leaves the inner world, he locates himself in Diamond City, buys a small house with a garage and a new car, a Car he would use for racing in MKDD. He soon finds out about the Golden Pyramid and decides to go after the treasure there, aka the events of Wario Land 4.
After that, with enough money and temporarily exhausted after the the 2 last adventures, decides to open his gaming business, aka the first WarioWare game, then well that game's ending happens where he attempts to run away with the money to no avail.
After that he decides to enter adventuring again, first with Wario Land Shake It (or Shake Dimension), but fails again, you know with that ending as well, then he tries the Telmet stunt in Master of Disguise, but once again fails.
Having given up, he returns to the Game making business, leading to our modern WarioWare series alongside the recent Game and Wario.
That's a little how the Wario timeline plays out in my head canon.
