>>57256499In terms of having rich parents? Alola and Paldea protagonists' families are capable of casually buying houses in tourism hot spots.
In terms of what they canonically earned on their journeys? Alola's postgame stories both give the player a million Pokedollars for finishing them.
In terms of how much money the player can spend? Platinum's villa furniture costs 2.5 million, all of Calem's possible clothes cost 2.2 million, Serena's cost 4.6 million, Elio's cost 4 or 7 million, Selene's cost 6.5 or 9 million, and Bulbapedia doesn't have total costs for SwSh or SV but there's a clothing item in SwSh that costs 150k with 12 color variations and SV has the fancy jinbei and auction items that start at 100k but can go for more so it's probably similar to the costs of the Alola games.
In terms of assets that don't directly translate to your in-game money? B2W2 has movies that can gross up to 1 trillion and join avenue.
In conclusion, either Nate, Rosa, or Ultra Moon Selene.