To preface, I am new to philosophy as a whole so apologies for obvious gaps in understanding of the literature. As an extension of this preface, the argument presented below was one I made as a high schooler with under three weeks of philosophy readings under my belt... it's accordingly pretty rough.

In a random philosophy class I took in Junior year of high school the professor introduced Berkeley's Subjective Idealism- df. "a philosophy based on the premise that nothing exists except minds and spirits and their perceptions or ideas." I, being an energetic kid new to philosophy, tried to build some sort of syllogistic argument to rebuke the theory. I was looking through my notes app recently and saw this argument and, after reading it in amusement, wondered if it can be extended as a rebuttal of classical theism as a whole (specifically the theory that there was a conscious being that preceded other forms of perceptible existence).

Here is a rough outline of the argument I posited against subjective idealism:
1. According to Berkeley, all that is are ideas and minds.
2. Ideas are mind-dependent; perceptions require a perceiver.
3. Thus, according to Berkeley, a mind had to exist before or come to existence simultaneously with ideas.
4. Non-existence cannot be perceived and something imperceptible cannot be perceived.
5. Minds have no perceivable structure of their own.
6. Thus, minds cannot be perceived or perceive themselves (from (4) and (5)).
7. Thus, all that can be perceived are ideas (from (1), (4), and (6)).
8. A mind cannot perceive something if there is nothing to perceive (from (4)).
9. For ideas to exist, a mind had to perceive (from (2))
10. Ideas exist
11. Thus, the first mind(s) had to be able to perceive (from (2), (7) and (10)).
12. Therefore, ideas had to exist before minds.
13. According to Berkeley, a mind had to exist before ideas (from (3)).
14. But since ideas exist, they had to exist before minds (from (12)).
15. Thus, there is a contradiction in Berkeley’s theory.

I also posited another argument to back this up, which intended to state that a mind cannot exist without some (presumably material/mechanistic) mechanisms for sensory or computational abilities.

1. To perceive itself, a mind needs some sensory and computational abilities.
2. Sensory abilities are useless without anything to sense.
3. The perceiver can only sense their own perceptions.
4. But to have perceptions it must have some sensory abilities (from (1)).
5. But sensory abilities are useless without any perceptions to sense (from (2)).
6. Thus, sensory abilities and perceptions are contingent on each other, and so they cannot arise simultaneously.
7. Thus, a mind alone cannot perceive itself.

Obviously rough around the edges but there seems to be some intriguing validity in the conclusion that it make no sense for a mind to exist without there also existing i) something that is perceivable and ii) the ability to perceive/sense. I am curious if you believe theres any validity in the argument against Berkeley but mostly curious if you believe this logic can be extended to rebut classical theism. This conclusion seems to imply that a conscious "God" that arose before all of creation is impossible because a) he would have nothing to perceive and thus have no content of thought or qualia, and ii) he would have no mechanism to perceive or sense.