You are actually wrong about the accelerometer, you're almost making the same error as the poster above. The accelerometer shows 9.8m/s² IF you are holding it

You are actually wrong about the accelerometer, you're almost making the same error as the poster above. The accelerometer shows 9.8m/s² IF you are holding it in your hand. And that acceleration is pointing up away from the earth, not down towards it. It is measuring the force of your hand/the table pushing it up to stop it from following its normal trajectory. If you drop the accelerometer, it will show 0 until it hits the ground. If you're holding it while in a plain, it will show slightly less than 9.8, but if you drop it will still go down to 0. If you take it into space, it will show 0 even when it is touching your hand, because it's trajectory is no longer curved towards the center of the earth.