I feel like universal artifacts are going to be a hard no from the development team. There's too much possibility of unrestrained power creep, and the game thrives on variety. If every single city can have the two or three best evolving buildings, then eventually they will.
I do think that there needs to a path, preferably a difficult path, to doing that. A player who really, really wants to have a particular building fully evolved should be able to do that, but it should take them a lot of effort, and/or a long time. Something like "phoenix (or bear, or mermaid etc.) artifact shards" in the academy, that cost 10 catalysts each and you need ten of them to make a full artifact. So a single evolve artifact costs 100 catalysts and a fully evolved building costs 1000 catalysts. Then artifact shards could also appear as a prize in events, With some daily prizes (or an option in one of the chests) being one, or two artifact shards (maybe at random). Thus making them very hard to accumulate enough of (since you need 100 the same to make a fully evolved building), but not impossible. It gives players agency in how hard they want to work for it, without denying it outright.