Besides, wouldn't that be exactly like our current physics? (Where we reduce until we find something fundamental like “electric charge just is and has this properties”, similarly for Quantum fields and the like -- and then how that composes and interacts with other fundamentals is the whole business.)
The composition problem is considered the hard problem of panpsychism. But as your intuition correctly points out, it is definitely easier than the original hard problem of materialism, which is a category jump from quantities to qualities.
The main difference is that physics is quantifiable, so we can come up with in-principle explanations of really complex stuff (weather forecasts, life itself, etc). With qualities it's a different ballgame, because we are talking about different subjects combining into one. Not saying that it's a dead end, but we haven't even yet started to define the problem, let alone solving it.
There are other more compelling roads. Rather than a combination mechanism, we can look at the problem from a decomposition perspective. This is easier because it's a really well understood phenomenon that we can actually study: the compartmentalization of one unified mind into separate minds, also known as multiple personality disorder or dissociative identity disorder. Here, we have a clear in-principle path to walk.
Would these be like the “easy problems” then?
Besides, wouldn't that be exactly like our current physics? (Where we reduce until we find something fundamental like “electric charge just is and has this properties”, similarly for Quantum fields and the like -- and then how that composes and interacts with other fundamentals is the whole business.)