This always boils down to the Epicurean Paradox.

So, most religious mythology (including Christianity) defines its god as 3 absolutes:

• All good (not a shred of evil)

• All powerfull (its will is our reality, period)

• All knowing (it’s fully conscious of literally everything that happens in its universe)

So how is it that evil can exist? Cuz we can see that clear as day, everywhere. God either…

• is aware of it, has the ability to stop it, and chooses not to, in which case it is not all good.

• is aware of it, wants to stop it, but doesn’t have the ability to, in which case it isn’t all powerful.

• Has the power and desire to stop it, but isn’t aware it’s happening, in which case it isn’t all knowing.

Every single attempt to answer the Epicurean paradox does so by rugpulling one of the three pillars and presenting god as instead only being two of those absolutes. (and if anyone reading this takes that as a challenge, feel free to give it a go).

How can this be explained, other than God doesn’t exist?

Either Christianity and most other religions are being deliberately dishonest about the nature of their gods, or, as you said, god doesn’t exist.