I'm actually fairly new to manpages as a format, but very familiar with Markdown. Frankly, I expected to find a whole bunch of redundant projects like this one, but have come up emptyhanded.
So far, I've used mandoc via SSH from my iPad to a shared macOS-running machine using a Siri Shortcut.
Inspired by this guide, my shortcut is using the following command to send markdown-formatted results to stdout:
mandoc -T markdown `man -w Repeat Item`