Civ I is probably the one I’ve played most. There isn’t a Civ I haven’t played, but I’ve been less into the series as it developed over time.
I don’t think the later games in the series are worse than the first ones, probably quite the opposite, but I’m just really into how basic the first game was.
Civ 1 is really just a dressed up war game and everything that’s not about crushing your enemies is not worth doing haha