I've been enjoying it a lot, but it's clearly an unfinished product at the moment.

To get into a little more detail, there's not a whole lot of features at the moment, but that's pretty par for the course. The launch version of VI seems similarly sparse in this regard, but its updates and expansions did a good job fleshing it out. What's there at the moment is mostly just a barebones collection of core gameplay systems, but I already think they're deeper and more engaging than in previous iterations.
Grouping units up for rapid deployment under a commander? Love it. Navigable rivers? Sign me the fuck up. Making the game's outcome feel like less of a foregone conclusion by half-time by soft-resetting at the start of new eras? Sorely needed. Love how they've re-worked independent powers (formerly city-states and barbarian encampments). Content is gonna come later.
It's a shame that the interface is total dog shit. People are complaining that it got dumbed down for parity with consoles, but if it's as bad on those as it was using a controller on PC (at my gf's place, so I was playing with my deck) then this is a sloppy execution that doesn't work well for anyone.

It's reviewed poorly because it just came out and is missing a lot of features (read DLCs) and bug fixes the previous civs already have. That and there is no British civ yet (unless they've added them recently-ish).

Didn't play much of Humankind, but from what I've heard, it was a great concept, but it lacked a lot of polish and got a little overhyped when it came out as the 'Civilization killer'.

I played Civ 7 after a few patches and I just could not get into it. I don't think I even made it into the second phase or age or whatever. Was so bummed by how lackluster it felt that I went and tried out Humankind, and despite a steepish learning curve I ended up enjoying it so much I played through 3 entire games.

I've been enjoying it, although it is still unpolished. I think ultimately whether you like the new direction (changes to the age system/picking new civs mid game) is going to be a matter of personal taste. To me, I now feel like my unique civ bonuses are always relevant, instead of just in whatever specific era. I also find myself more engaged in mid to late game.

But I've also read a number of comments where people prioritize other aspects of the Civ experience, and those folks do NOT like the changes to game flow. Your mileage may vary.

It has bad reviews for the same reasons most games got bad reviews: expectations. It looks beautiful and it seemed they put a lot of work into the mechanics (although the age system is controversial) and on release both these things were true but there were major problems they hid in the pre launch promotion, the biggest one is the UI. Everyone who got early access to review/be sponsored (some months in advanced) told them to fix the UI to make the game perfect. But they did not, and it is still very flawed. If it had maybe a few more months in development it would be a great game.

Oh also Denuvo, pushing DLC despite the work needed on the base game and the high prices probably aren't helping reviews.

It's worth mentioning I haven't played it yet (waiting for a sale), I am just repeating what friends/content creators who weren't bribed by T2 have told me.