Jaykobo,what is your first language? please do a load test on your battery
consider an ignition kill switch if the engine is hard to crank due to high static spark advance.
do a draw test on the starter.
do a load test on your battery using your cables if the battery is good.
Do a draw test with your starter using your cables,all to make sure the parts work together.
Is you battery in the stock location?
Put a torque wrench on your engine to measure how hard it is to rotate your engine.
Do a starter motor draw test with the ignition disconnected.
do some math