

If they know what email and reddit it are, Lemmy should be pretty easy to understand, at least from a user-perspective. Replace reddit with Twitter/Bluesky for mastodon, Instagram for pixelfed, etc, etc. I don’t think understanding how email works at a tech level is important for being able to use it. Ditto for fediverse.
Another way to differentiate would be things like rendering technology. While raytracing is starting to be partially utilized a little bit, I’d hardly say it’s taken over yet, so there’s not much technological difference between a 360 and a PS5. Mostly boils down to more cores and faster with some minor extra features. Far more difference between even the SNES and the N64 than between the PS1 and the PS5 imo.
You could also use Internet access as a determinant, but then even snes and Sega Genesis wouldn’t be retro (at least in Japan).
Could just define retros as anything that fits at least one or 2 of those 4 characteristics of retro video game consoles, but the xbox360 is pretty much modern by all of them.