I doubt it. Nix has a ton of infrastructure and contributors there. Plus they wouldn’t gain anything immediately tangible from it. Codeberg is still git with a very similar UX to GitHub. Not the same can be said for Savannah.
That doesn’t mean it’d be a bad choice in the long run. But still.
Some stuff turns to e-waste because it’s no longer supported by software. Some stuff turns to e-waste because it’s just so goddamn old. The last ones of these architecture had a whopping 233MHz. My first PC that I got new as a kid was faster than that (must have been a Pentium II, while i586 is Pentium). I highly doubt there are many of these systems left in operation, especially not with new kernels.
Regarding security, it’d be interesting to see how secure it actually is. Yeah, the individual endpoints might be protected better, but is Plex the company maybe a single point of failure?