RAW, the feat clearly states "you can try to telekinetically shove one creature," and we know there are no size limitations. You could attempt to shove a giant or a dragon.
RAI — is there some reason it would be game-breaking to extend this to objects that aren’t nailed down (like STR-based Push/Drag), or to try breaking down doors? Better yet, is there a general rule about the equivalence of moving creatures and objects I might be missing that would apply here? If your Telekinetic DC is 15, that’s about the average roll of a STR 20 character, and it feels like an oversight that you can shove massive beasts but you can’t shove a rusty bucket.
EDIT to illustrate the counterintuitive nature of the RAW text: Let’s say you’re behind bars in a jail cell and the guard with a key ring on his belt is 10 feet away. With Telekinetic, you could pull him 5 feet toward you and then attempt to snatch the keys. But if you kill the guard with a ranged attack and his corpse drops to the ground, suddenly Telekinetic no longer applies? Let’s stipulate that Mage Hand is useless here because it’s not strong enough to yank the keys off (maybe you could use it to remove the guard’s belt, but that’s not really the point of this thought experiment). Or you could say the key is chained to a table. You can pull the 200-lb guard’s entire (living) body at a rate of 5’/round, but you can’t pull a 50-lb table?