Isn’t pantheism the same thing as atheism?

[Belacqua]

That's true.

It means that because he is pure act, all potencies in the universe are actualized and aimed toward him.

Some people thinks it means he can do anything, but that's not right. He can't make a four-sided triangle, for example.

I go by the definition of the word in the dictionary.

This is from Merriam-Webster
omnipotent=
1a. having absolute power over all
1b.relatively unlimited in power
1c. having or regarded as having great power or importance
2. having virtually unlimited authority or influence

I would say that the jewish god has absolute power over reality.
If you want to call a 4 sided shape a triangle, you could.
If you want to have a 4 sided shape that also has 3 sides, then you have a logical problem. No one can be omnipotent enough to change the rules of logic.
The 1b makes some sense with respect to logic.

It’s the same with mathematics. No one is omnipotent enough to make the number 5 disappear. Again, this is a matter of logic.

If you want to define God in a certain way and then not believe in what you've imagined, that's your right.

If you think that God could contradict the laws of logic, that's OK with me.

This doesn't mean that Christian theology agrees with you.