They’re just categorically different, there isn’t an “inside” or an “outside” in the sense of spatial structure as that is something derived a posteriori as part of thought.
I’m not sure what it would even mean to say reality is “thought”. If I try my best to stop thinking about things does experiential reality just disappear? Not for me it doesn’t. Maybe for you.
What is thought of as opposed to thought itself must necessarily exist prior to the thought in order for it to enter into thought and be what is thought of in the first place. I mean, it’s just self-evident, is it not? If all thoughts cease, reality doesn’t disappear. It’s always there independent of whether or not thought is applied to it or not, whether or not there is an attempt to interpret it. It exists independent of any attempt made to formulate a subjective interpretation of it. That’s all that is meant here by “objective,” that reality is what it is entirely independent of what it is subjectively taken to be.
There is no mind-body problem in the first place. All dualisms and idealisms are circular as they start from the premise that reality is subject-dependent then work backwards from that conclusion, but they never justify that premise. Even many materialists fall for it.
Objects are in the category of thought but not in some spatial “realm” or “world” of thought. It is definitional, linguistic, not a statement about ontology.
From an a priori standpoint there is no material, there is just reality. Our understanding of material reality comes from an a posteriori standpoint of investing it, learning about it, forming laws etc, and we do come to understand thought from an a posteriori lens as something that can be observed and implemented in other systems.
Usually thought itself is not even considered as part of the so-called “hard problem” as that’s categorized into the “easy problem.”
They say existence is “mind” which includes both thought and experience which they both argue are products of the mind, and so if we start off with thought and experience as the foundations of philosophy then we’re never able to leave the mind. That’s how idealism works, the “thought” part of basically the “easy” problem and the “experience” part is what entails the “hard” problem since even idealists would concede that it is not difficult to conceive of constructing an intelligent machine that can reason, potentially even as good as humans can.