Hi there,
It seems to me that you better start off where it all begins, i suppose you have a simple multimeter?
Set the meter to DC voltage (range 20V) and but the test leads to the positive and negative of your battery, see much much it reads, it should be 12.6V or more.
When that’s ok, ask a friend to start the car while you are still monitoring battery voltage, if while the engine cranks the voltage drops below 9.5V your battery just can’t produce the power to crank, supply voltage to the ignition system and to the fuel pump at the same time. It’s not so that if you hear the engine making a cranking noise it is actually providing enough compression to start…
If you could check that first you can rule that problem out…
Greetz