You can download your entire posting history in just a couple minutes then filter that on your own computer.
Particularly if you want just your mmp posts by themselves, not in the context of each entire mmp thread, this might be a lower effort way to do things.
The posts themselves download as a huge CSV file. So you will need to do some spreadsheet wizardry to tease out the mmp posts. But I bet that’s well within your occupational skillset and shouldn’t pose any particualr challenge.