Split STL into Multiple Parts

I already have a single, watertight STL file but I need it broken down into several printable sections—definitely more than five—so I can assemble the final piece with minimal post-processing. The whole aim here is easier assembly: each segment should fit together cleanly once printed, with well-thought-out joins (simple keyed pegs or tongue-and-groove edges are fine as long as they remain flush).
Please check image sample , nothing complicate, will always be basic simple model , some easier thandn the model , some more complicate
Need 1 per day for a month to start, so will take the cheapest offer
Freelancer makes the cheapest 10$, but I am looking for less