Boy, when you're wrong you really commit, don't you. Let's try to lead you out of this.
First of there's theism and deism. Theism states that there is a god who created the universe and maintains it. Deism says that God doesn't have anything to do with the universe it created. There we have several propositions already including a declaration that theism is not merely the belief that God exists.
Blimey Vlad - you really are digging yourself in deeper and deeper. Yes I am well aware of what deism is, but it appears that you do not understand what the strict definition of theism is - see below.
Secondly look up the definition of theism.
Yup, you mean like this one - I trust you consider the Cambridge Dictionary to be authoritative:
https://dictionary.cambridge.org/dictionary/english/theism'belief in the existence of a god or gods'Now I know that some definitions add some exemplars of the type of god, but that isn't part of the strict definition at all and is both superfluous and also confusing. So theism (see definition) is belief in the existence of god or gods. Deism is a sub-category of theism in which the god is non-interventionist. But a deism believes in the existence of that non interventionalist god and is therefore also theist.
And you can see the non-sense of trying to define theism in the context of a particular type of god alone when you look at the flip-side of theism, which is of course atheism. An atheist is someone who does not believe in the existence of god or gods, not someone who does not believe in a god who created the universe and maintains it, but believes in a god that does not maintain the world.
So image someone who fervently believes that there is a god, but that although that god created the world, having done so that god does not intervene in the world. That person isn't atheist, that person is clearly theist (as they believe in the existence of that god) but also deist.
Given the description of God in theism, creator and maintainer of the universe, That description is not a 'true for me only' declaration.
Show me exactly in the definition of theism I quote above the part that described the type of god ... of yes, there isn't one.