The One thing that you mentioned about the oil leak could be the cause if it leaked on your starter. The easiest thing to do is possible is take it to an Auto Zone and have it tested, it's free. Especially if it's fine till you try to turn it over if the oil impeding the circuit it can't get past the starter to crank, it will click at the solenoid.
Here's a good video that covers all the things you can do to get to the bottom of the problem
https://youtu.be/s6OXK1XztI0?si=rm90P31ZI-BQokxr
Good luck🤞