After spending 50 hours in terraria on a Macbook Pro M1 (2020), I can say with no doubt the game does not run perfect. In the early stages it does seem to run very well, but fighting the Eater of Worlds drops the frames to barely playable, using Summoner Whips destroys the performance, The Destroyer (Mechanical Eater of Worlds) also drops the fps. Using a Summoner Whip on any of these bosses causes the game to run in slow motion even with FrameSkip ON. After gathering all the npc on the world, the performance also drops. Using a battle potion, causing more enemies to spawn also drops fps.
In short, if there are effects (like sparks from the Durendal Whip), lots of enemies or NPC's (Eater of Worlds or Destroyer "segments" count too) the performance tanks.
It is a bit better if not using the summoner class. But after testing it with Mage and Ranged classes, after acquiring late-game armour and weapons which have flame effects, afterimage effects etc. it gets to the same poor performance level.
Specs: MacBook Pro M1 (2020) 16GB macOS 12.0.1 Monterey