Building on what Mykan said, you might find ElvenGems' comparison guide useful:
https://elvengems.com/ancient-wonders/comparison-guide/
I have three cities. So far, Harandar only has one AW, the Golden Abyss. For me, that's a must, and if I make any more cities, it will be in each one of them as well. I find it too beneficial to not have. Each of my cities have it. And it is the one wonder that I will, without fail, use time boost instants to complete immediately after I set it to upgrade. I'm not waiting a day or more to get my pop boost and my 3 hour gold reward if I can help it.
But Needles is only in my Sinya city so far, and I probably won't build it in Harandar until I'm much later in the game. Building it in Elcy is taking a back seat to others that I've decided upon based on the benefits factors that comparison guide was useful in letting me look at 'at a glance'.
And to illustrate Mykan's point: Darielle said that early on, she wouldn't have considered the Dwarven Bulwark a beneficial wonder. But for me, it's the space of 2 level 17 armories, each of which only gives me the ability to produce 60 units. My DB currently lets me have 178 (it will be more when I activate that squad size research I skipped and forgot about that I'm waiting on the 23rd's quest to be open for). In Elcy, that's a must as I go through troops like water if I don't have the DB and try to sleep for more than 3 hours at a stretch. And, yes, I have 2 lvl 17 armories
plus the DB - I put the other 2 armories in storage for now. Even at level 1 (133 units), the DB was a better placement for me in that city.
By the way, this:
Frankly, I'd rather put those kp into a wonder that I know I'm going to keep forever rather than lose them to something I'm going to eventually sell.
is an excellent point when making decisions on AWs. While I'll eventually use up the goods it takes to build a Tome of Secrets, it's only so I can sell it immediately and break down the runes I have to make broken shards so I can forge runes for wonders I have trouble getting runes for. (Like Mountain Halls when I reached level 5. No runes to be had anywhere, despite all the levels of the tournament that I have that produce runes.
) The comparison guide helped me weigh the pros and cons for what I want to achieve when making that decision.