I am speculating about the value of Tycho Brahe’s - for his time - accurate observations and Kepler’s calculations.
Might it have been possible for Kepler to formulate his laws based on Ptolemy’s system, assuming he adapted the Earth’s position in a heliocentric system?
For example you might expect that the period of the planets might be known relatively accurately also from Ptolemy’s data.
Similarly, if you were ready to accept elliptical orbits, planets such as Mercury and Mars might give some input to the second law. I realize that there is a component of circular reason involved here, in that you must be open to the laws from the beginning in order to want to make such tests using Ptolemy’s system.