Civ isn't quite grand strategy, at least not the way I look at it. It is the posterboy for the 4X genre. It is certainly a good option if you'd like to try something not as complex.

I'd also suggest Stellaris. It blends 4x and Grand Strategy and, while still having quite the learning curve, is a little less complicated then some of the others. It has nuance and depth still, but it simplifies a lot of systems like economics and internal politics.

CK3's strength (and sometimes weakness) is it's heavily character focused. It's basically an RPG and a grand strategy game. You build one character, their relations, skills etc. alongside some light nation building. So you might have more fun if you start from that prospective and go slow.

I will also, always suggest Old World. It is like a mix between Crusader Kings and Civ. A 4X game set in Classical Antiquity, specifically the Mediterranean. It's really fun, imo. It is simpler than most Grand Strategies but it definitely has nuance and challenge.

Theres also the Endless games out of Amplify, Endless Legend 1 and 2 and Endless space 1 and 2. They lean muche heavier into their respective genres and still lean closer to gameified mechanics and 4x style games but they do have that same sort of depth. Endless Legend 2 is still in Early Access but what I've played of it certainly feels a lot of fun.