Read up on the equivalence principle.
And basic physics as well, while you're at it.
Holy Crap! Yeah you are right! Forgot about that!
Gravity is indistinguishable from acceleration. The elevator thought experiment. Damn. That was rather stupid of me.
You forgot a tiny word that makes a world of difference, and EnglshGentleman is trying to savor his hollow victory instead of explaining it to you.
Gravity is
locally indistinguishable from acceleration.
If you are inside an elevator without any contact to the outer world, gravity is indistinguishable from acceleration. But if you have a window and see the planets, those are not in your local frame of reference and you can distinguish a planet revolving around the Sun from a "planet" hovering above your head.
Also, the Coriollis effect is a clear demonstration of the effects of gravity in a non-local environment. The hurricane that passes over the USA is not in the local vicinity of one that forms close to Australia, and you can see that they are different.
If you want more examples, look at satellites. The Flat Earthers have been unable to explain how they orbit Earth so they declared them "a conspiracy", but in the real world they orbit because they do not stay in one local vicinity.
So, when you get a lesson of physics from a flat Earther, next time you should show a lot more distrust.