Note it is always implied that free-fall frame without qualification means a free-fall frame NOT rotating relative to the observable universe.
Only the differences in the external gravitational field relative to the mass-weighted average external gravitational field affect the internal motions. The mass-weighted average external gravitational field is often to good approximation the external gravitational field at the center of mass.
The differences are called tidal forces.
Therefore, every surface point does NOT define exactly an inertial frame (see Mechanics file: Acceleration and Inertial Frames).
However, you can convert it to an inertial frame if you like (see Mechanics file: frame_basics.html: Non-Inertial Frames Converted to Inertial Frames; frame_basics.html: Rotating Frames and the Centrifugal Force and the Coriolis Force).
However again, the acceleration is actually so low (⪅ 0.03 m/s**2) that for most purposes (but not all purposes), you can treat every surface point as defining a LOCAL inertial frame (i.e., an inertial frame at the point and nearby surroundings) without conversion. This is why we can use Newtonian physics in the approximate inertial frame of any point on the Earth's surface for most purposes without conversion.