You are conflating explanation with assertion.
Anyone can posit baseless assertions that hypothetically account for things, but that doesn't mean they have explained those things. Explanations are not baseless. Explanations incorporate data. They provide a mechanistic understanding for predicting the outputs of a system.
Physicalism is not baseless. Physicalism incorporates data. Physicalism provides a mechanistic understanding for predicting outputs of systems. Physicalism explains 99.99% of our reality.
Idealism is baseless. Idealism does not incorporate data, it just asserts things arbitrarily. Idealism does not provide any mechanistic understanding of why things are the way they are for predictive purposes. Idealism explains 0% of our reality.
When choosing between metaphysical theories, explanatory power is the primary epistemic virtue. Simplicity only becomes relevant after explanatory power has been maximized.
Physicalism outperforms idealism in explanatory power. It underpins our most successful predictive and practical frameworks—from physics and biology to engineering and medicine. Until idealism can generate more accurate and useful predictions than physicalism, appeals to simplicity are premature.
It doesn't matter if physicalism is missing an explanation for consciousness, as on total it still explains more than idealism, and should hence be chosen as the de facto theory until a better theory can explain more than physicalism.