Easily Europa Universalis 4. It's a grand strategy game, which means it's an Excel Spreadsheet with better UI.

This game specifically since it was popular in my friend group, got both free and paid updates for more than a decade, and it is rather low energy so you can either focus on talking with friends or barely hold on to consciousness at 3 A.M. when you said you'd go to sleep just after annexing one. random. duchy. which takes way longer than it should.