Learning The World by Ken MacLeod
The book alternates chapters between two unique worlds. The first is a kind of interstellar colony ship on a 400-year voyage from the fringes of the human colonized sector of the galaxy out to an un-colonized star system. It takes place many thousands of years in our future. It's a vast structure with artificial lighting in the "sky" designed to emulate the sun, with periods of day and night, a large region where generations have been living in suburban and rural Earth-like settings, etc. It's big enough that there's an atmosphere area where aircraft fly and an area were the atmosphere is too thin higher up. There is a region where zero-G adapted crew members live and work.
The other world is a planet in the system the colony ship is headed for. This planet is inhabited by winged people. There technology is mixed, but is reminiscent of early- to mid-20th century Earth. But there are various interesting factors - animals related to the winged people but which they consider merely animals, going to an outdoors "bar" and eating fermented fruits, a different religious tradition, etc. There are three major national powers on the planet. Although we learn a bit about all three, we mostly see scientists living in one of those nations.
As the colony ship decelerates on the outskirts of the star system, an astronomer on the inhabited planet notes a previously unknown "comet" with some peculiar aspects. He and a physicist friend discover what they come to believe is a starship from elsewhere. They also find evidence that it is coming from the direction of a group of stars that seems to show a spreading pattern of signs of life.
Meanwhile, the people on the starship start to see unusual signs from the planet that could suggest complex life. This is extraordinary - humans have been spreading through the stars for 14,000 years and have never encountered complex life anywhere else. Although this is an exciting prospect for some, it raises issues for others. The colony ship is, on one level, a financial system with much being dependent on investments made with the expectation of being able to own, mine or otherwise capitalize on the entire resources of the star system. Furthermore, the youth aboard the ship have been raised to be anxious to get off the ship and start building their own enterprises in this star system.
Then, the human ship actually gets video showing winged people who are clearly intelligent. And the people of the planet begin to make telescope pictures of the colony ship and accidentally receive a transmission from the ship which includes video of a human.
Both civilizations are faced with an entirely new situation.
So in one book you get: a view of human civilization in 14,000 years, a view of an alien civilization, a first contact story presented equally from both sides, and the "first contact" starts with a period of knowing the other exists but not actually meeting as seen by both sides.
Some readers might find that the aliens are different, but the book doesn't explore very far into the alien-ness of non-humans. Of course, that is a tricky job for an author. If an author writes about aliens whose lives, priorities and point of view are too out-of-sync with ours, it will just seem like a bunch of gibberish to the reader. In Learning The World, the aliens are rather human-like below the superficial level. (And at the end, in a couple of regards they are perhaps more like what humans consider their better side.)