I'm not sure. Similar communities at different instances can have very different rules and vibes. There's a reason people prefer talking politics on Beehaw versus Hexbear.
I like the Kbin solution so far. Leave communities separate but cross-link and deduplicate individual threads from multiple communities in your feed. The implementation at Kbin is still a bit flawed, but the idea is sound.
I never understood why people run Ubuntu on servers. It's madness. Ubuntu is a fork of unstable Debian packages. You don't want unstable on your server!
Ubuntu on Desktop I can understand. Back in the days the Debian release was really long so much software was a tad outdated after a couple of years. But Debian had a much faster release cycle now, and had pretty much incorporated all the good stuff from Ubuntu and left the bad behind.