Don’t label yourself as a theist or an atheist.
It’s very difficult to be an atheist, do you know why?
You say that something is not existing.
When you say that something doesn’t exist, you should know everything about the universe to be able to say that, and it is impossible to know everything in the universe.
The same is with a theist also. Believers or non-believers, they are on the same boat because both of them think they know it all.
I would say, it is better to be a seeker of truth. If you are a seeker of truth, you don’t have to believe things that you don’t know.
You know you exist and you believe you exist, then explore who you are, forget about God, keep God aside.
Let’s just go with this self-inquiry ‘Who am I?’