Gateway: after Splendor, where do you go next

Splendor clicked for my friend group — we actually finished games without rules fights — and now they’re asking ‘what’s like this but more.’

I don’t want to jump straight into Terraforming Mars and scare them. I also don’t want another pure solitaire race where nobody talks.

We usually have 3-4 players, occasionally 5. Games under 90 minutes have a much higher chance of hitting the table.

What’s the best ‘second step’ after Splendor that adds depth without adding a rulebook novella?

Bonus points if it teaches a mechanic they’ll see later in heavier games — drafting, routes, engine upgrades, whatever.

I’ve heard Century mentioned a lot but the trilogy thing confuses me on where to start.