Occam’s razor applies between theories only if they explain the data equally well. This is not one of those cases.
As an example, the existence of an external world that follows physical laws explains why we experience a particular kind of world rather than another. Without this, the fact that our “experience” follows laws becomes a complete mystery and a brute fact, especially since there is nothing within the act of an immaterial experience that necessitates order.
In other words, solipsism has no explanation for why we experience X instead of Y. The existence of a world combined with the laws that govern it do tell us why we experience X instead of Y. Thus, solipsism is inferior when it comes to explanatory power.
Furthermore, one can use arguments by analogy to infer the existence of other minds. In our experience, we can see other humans that behave and look very similarly to us. This similarity can be used to infer other similarities such as the existence of other minds.