Smash Bros Ultimate: Is Doc's the only Gym in the game?

There are numerous dojos and (at least) 3 exploring options. Is Doc's the only gym in the game? I cannot find any others, both playing and searching online, but it seems odd they'd have an entire category for a single location (instead of making it a "level up dojo" or something).


Solution 1:

It is the only Gym. So you are limited to only 4 spirits training at the same time.