I explored options when I had a pile of MBOX files to work with some time ago. I finally chose Kernel MBOX Converter. It turned all my MBOX files into PST files without changing the folder structure. It also fixed some MBOX files that seemed corrupted. That was the reason I chose it because other tools I tested could not handle those corrupted MBOX files. The user interface was easy. I did not have to search for instructions. I recommend trying the version first to see how it handles your MBOX files before making a decision.
https://www.nucleustechnologies.com/mbox-converter/
I explored options when I had a pile of MBOX files to work with some time ago. I finally chose Kernel MBOX Converter. It turned all my MBOX files into PST files without changing the folder structure. It also fixed some MBOX files that seemed corrupted. That was the reason I chose it because other tools I tested could not handle those corrupted MBOX files. The user interface was easy. I did not have to search for instructions. I recommend trying the version first to see how it handles your MBOX files before making a decision.
https://www.nucleustechnologies.com/mbox-converter/