You are right that Mac Mail's export is mbox rather than individual EML, but there is a genuinely easy native trick plus conversion routes, so the easy way first:

The drag and drop trick, the easy native route: Mac Mail lets you drag messages directly from the message list to a Finder folder, and doing so creates .eml files, one per message, right there. Select the messages you want, drag them to a folder on the desktop or elsewhere in Finder and each becomes an individual EML file. This is the simple built in way to get EML out of Mac Mail that most people miss, no tools needed, ideal for the one per message result you want.

The scale of the drag trick: it handles a selection well, so for a folder of messages, select all in that mailbox and drag, producing all of them as EML files at once, which covers most needs without any conversion. For very large mailboxes the drag can be slower, batching helps, but for typical volumes the drag is the easy answer the question asks for.

The mbox conversion route, when you already have mbox exports: if you have exported mbox from Mac Mail or need the export path, converting mbox to individual EML is straightforward with the same tools this forum's MBOX threads cover, an MBOX to EML converter or Thunderbird with ImportExportTools NG importing the mbox and exporting individual EML, the route when the drag is impractical or you already went through mbox.

The choice: the drag from Mac Mail to Finder is the easy direct way for getting EML out, wanting nothing but Mail and Finder, so try it first since it directly answers easy export to EML and fall back to mbox export plus conversion only if the drag does not suit your volume or workflow. The drag trick being native and immediate is genuinely the easiest path and the one worth knowing, since most people assume mbox is the only export and miss that Finder drag produces exactly the EML files they need.