I don’t really think of Notion as “markdown” but I suppose you’re right since we support a bunch of markdown conventions. Some things are different though like `> ` is a toggle block, and `” ` a quote block. Unfortunately we already abuse / for a command menu, which is by far my least favorite feature. I want to make a setting to disable it but it goes against our anti-settings philosophy.
I will say that forward slashes are still more common in regular english text even among non-programmers than underscores. For example, listing options a/b/c.
And you know, URLs.