Why are there fields?

It's turtles all the way down, and it fundamentally comes down to "why something rather than nothing"?

Nothing has no potential to create anything because it's literally nothing. It can not have potential.

So where do these crazy forces, fields, the quantum observer effect come from, out of nothing?

We will never find an answer to that question because it is literally unanswerable.

Then putting the "god" argument over the table seems either lazy or antropocentric.

The correct answer (as from today), it's "we don't know". You don't need to put any god, "energy" or whatever myth you know over ignorance.