Nice work! Now you can start playing game lol...I realized after my first clear how extensive the endgame content is, but it's very addicting and a fantastic game (and I normally don't care for roguelikes).

I beat it first with bow, I believe I had the hammer upgrade that changed it to rapid fire, combined with some heavy +% damage boons and probably Athena dash.

A few opinions:

Athena dash is probably the best standalone boon in the game. Almost all attacks can be deflected, including most melee ones, and it's an invaluable skill for surviving the last two boss fights. Picking up this boon probably doubles my chance of completing a run.

The Demeter and Artemis duo boon is super OP and just melts bosses. That got me my first shield clear, I barely used my actual weapon and was just casting most of the time. There's also Demeter boons that increase the uptime of the cast and adds chill to it.

Zeus's chain lightning attack is fantastic on the rail and fists. It's hard to get the right combo, but even better is the Poseidon attack and then the Poseidon and Zeus duo - the bad thing is that if you don't manage to get the duo boon later, Poseidon attack on these two weapons sucks by itself.

Other than that, just experiment and see what works for you. Weak, fast firing weapons = flat damage increase boons (Zeus, Dio, Ares), strong and slower weapons = +% damage boons (most of the others).