Both casual and online competitions
Game Freak breaks down both casual and competitive angles, as the former will return with an anything goes “any Pokemon” setup, in which results are not recorded for posterity. Ranked battles will have sorted tiers of ranks, with the master ball tier serving as the top of the pops. Renting teams will allow folks to use IDs to both share and rent Pokemon based on teams that other trainers use. Oh, and you need Switch Online to use the battle stadium mode.
You can find a breakdown below.
Scarlet and Violet battle modes: Casual Battles
These are low-stakes battles in which results are not recorded. One appealing feature about these battles is that you can use any Pokémon.
In these battles, you will be able to test your battle skills against Pokémon Trainers from all over the world. Your rank will change depending on your battle results. Trainers are sorted into tiers based on their ranks. If you can reach Master Ball Tier, the topmost tier, you’ll have a chance to vie to be the best Pokémon Trainer in the world in fierce battles.