After rescuing some random NPC, Rival Max dropped a pretty cryptic hint: basically I had to backtrack to Orpimence City, get to a hidden section of the Broadcasting Station and get a Meteor to get those scientist out of the way.
From then I can finally reach Lapizula City which, as expected, as a Psyquic type Gym which mixes Strength Boulder Puzzles, Sliding puzzles and Teleport tiles oddly enough