edit: ok you're quite right there are other ways out of the conundrum like idealism
There is another monist view though, one that sometimes gets called idealism, that says there is nothing else except for mental entities or causes. I lean towards this view.
The challenge for naturalism is to explain (or explain away) consciousness (the mental). We call this challenge 'the hard problem of consciousness'. The challenge for idealism is to explain (or explain away) the physical. However, there is no analogous 'hard problem of non-consciousness' (but the explanation of this would take an unreasonable amount of words that I cannot fit here).
Well don't lean on it too hard because its not very solid ; )
There absolutely is. If the world is all ideas, then it's just as impossible to explain why different minds have a coherent shared illusion of the physical world, or even any kind of communication between minds at all. I think it's much easier to reject the concept of consciousness in a materialist world view than it is to reject the inexplicably shared physical world in an idealist world view.
Of course, there is the simple and self-coherent answer of solipsism, but that's a kind of an intellectual dead end, there's nothing really to discuss about it.
It is far from impossible. There are many idealist models. Here is one: there is a central consciousness (call it God), and God is able to give experiences to other consciousnesses, and those consciousnesses can communicate back to God.
On that model, there is a shared world because God gives experiences to these other consciousnesses as of being in a shared world. The other consciousnesses, in turn, communicate back to God what they will, and that influences future experiences that God gives to those other consciousnesses. That gives a shared illusion of the physical world.
Note that whether you're a naturalist or an idealist, you're going to postulate some things as true without justifying them. For the naturalist, they postulate the existence of physical things without explaining why the physical exists at all. For the idealist, they postulate the existence of mental things without explaining why mental stuff exists at all. If the idealist asks to be granted the above simple postulates, then a coherent shared illusion is possible. I'm willing to grant the physicalist whatever physical postulates they need, and from that I would like to see how they explain (or explain away) consciousness.
If I take a camera, a microphone, a speaker, and some other sensors and feed them into a CPU/GPU and self train it to have an understanding of its capabilities (internal/self) and the world around it (the external), this this consciousness or not? If I light a fire near this 'smart' computer via it's sensors it can detect the heat and move farther away. If I give this computer a complex task that it has to calculate multiple steps to achieve before it acts, is this not mental work?
In LLM based systems we can't really figure out how this occurs because the computational complexity of the operations is too high, much like brute forcing encryption, getting to the answer of how it's working isn't impossible, you'd just have to burn the visible universe to figure it out.