If your goal is to view and search MBOX files easily, the simplest option is to use an offline MBOX viewer. Most offline viewers provide built-in search, filtering, and quick preview features, so you can browse emails without importing them anywhere.
You can also use Mozilla Thunderbird with the ImportExportTools NG add-on to import MBOX files, then view, search, organize, send, and manage emails normally. Since you mentioned export, this add-on also lets you export emails to formats like PDF, EML, or TXT.
Another practical option is an MBOX converter tool such as BitRecover, which is well-trusted in the industry. It allows you to convert MBOX files into other formats for easier viewing, searching, sharing, or long-term access