Never played the Civ series before, but I'm totally into strategy games. Recently got 200 hours into Pennon and Battle and kinda burned out now. The Heroes of Might and Magic: Olden Era which I'm hyped for isn't out yet, and there's nothing else in the strategy genre grabbing me. Was about to jump into Civ 7 but saw the mixed reviews... ugh.
If you're not really into the civilization series, I would always wait when the game has a huge sale.
I started with Civ5 during a 10$ sale with all expansions, 200 Hours. As a treat I bought Civ6 on launch, which while slightly barebone (all civ games are on launch) was really fun, and after buying the expansions and a couple DLC I got 500h on it so clearly a good investment.
I would put Civ6 and Civ7 in your wishlist to get notified when there's a sale, and see if you like it or not after the fact.
The current reviews for 7 are mostly about the UI and the limited selection of civs to choose, also for some reason some players can't bare the idea of stopping the game at the cold war just before the moon landing.