Why are you trying to gatekeep what is or is not a homelab. Just because it isn't sufficiently complex doesn't mean it doesn't fit the definition.
It looks to me that rolling your own media center is something to experiment with and learn something from.
Not to mention even if it was just a Plex server, that still meets your criteria.
It grew over time to serve many purposes, has seen many stopped/failed attempts, has had many lives (I mean, recreate from scratch to learn X, Y or Z).
There's not a particular day or a particular addition or a particular level of complexity when it became a homelab, I think of it as such from day 1.