>>41318341Sword/Shield's postgame amounts to a 2 hour quest where you help Hop catch a legendary, followed by a battle against Eternatus, followed by another battle with it where you can only lose to it if you actively try. The other things are spamming raids, and the Battle Tower, which has you fight generic NPCs that can't Dynamax (but you can) until you face Leon.
Also, it has no limitations at all on what you can use. Do you want to use Zacian? Go right ahead. Want to run Zamazenta? Knock yourself out. Eternatus? Of course. All fucking three? It's a legitimate strategy.
The Battle Tower's only modes are 3v3 Singles and 4v4 Doubles - there are no Super Singles/Doubles, and no multiplayer option. The Battle Tower is divided into rounds, which have no rewards, eventually getting you a battle with Leon, and beating them increases your Rank. The maximum Rank you can get is 32, and this is an inevitability because not only can you use whatever you want, but the only "penalty" for losing is the current round you're on resets and you don't get to see Leon.
