For the last century, the accepted theory is that gravity is indeed not a force but a manifestation of the space-time curvature. That’s one of the main points of general relativity.
If you look at the proper expression that calculates it's force, it becomes clear:
F = G * m1 * m2/ r^2 (so, gravity is the force between masses).
P.S. G is the universal constant of Gravity here, not the gravity itself.
That distant memory came from engineering school, where it was classical mechanics all the way down. The only non classical stuff was just a tiny amount in a first year physics paper.
Then again, maybe the way classical physics got taught was a bit different after Einstein so as not to directly contradict relativity. Eg maybe before relativity it really was described as a force?