It is beyond my mind how last two civ games have UN-like mechanic (overcomplicated abomination in civ6) but no simple, basic, regular, often happening constant of human history "let's just ally ally each other to support each other in both offensive and defensive wars". That's it. That's the entire concept. Basic, simple and universally human thing, and generates entire layers of depth. Bonus points if alliances may turn into blocs of more than 2 countries - all the time, not just in the endgame, see for example mamy Greek wars, such as the collapse of Antigonus, taken down by the coalition od three other heirs of Alexander the Great.
Civ6 has a ton of overcomplicated, board gamey, arcadey, abstract diplomatic mechanics, utterly disconnected from both intuition and immersion. We get medieval UN which works like slot machine and creates the philosophical paradox of voting contest between parties who don't know about each others existence (what drugs do you need to take to even think of such game mechanic - and then actually implement it). We get emergencies which I can't even explain out of context lol, basically I am suddenly nuked with thousands of gold im exchange for some arbitrary condition. We get like five separate types of "alliance", each with different metters and buckets to fill with points and arbitrary bonuses out of thin air. All this enormous "diplomatic" mess and I still cant see the simplest, most basic concept to happen as a rule of a universe in this game: "Few small frustrated guys conspire to beat one scary big guy together and actually do that". That's it. That's everything I want. No another 50 types of currencies and game systems I have to learn from wikis and lets plays.
Fortunately HK seems to move in the direction of mechanics more grounded in reality and grasped by mind of human beings. But, returning to the core of a topic, I do hope it has some proper in game tutorials to learn them without studying wikis, forums and YouTube lets plays.
Oh and by the way, it really irritated me when some Paradox game has really counterintitive, overcomplicated mechanic and fan's answer is for me to watch lets plays of some youtubers. As if I had nothing better to do rather than sitting for hours watching other people playing the game because it doesn't explain its own rules. There is the difference between hours of entertaining "learning" the game via deliberate design of exploration, experimentation and slowly mastering your skills, and literal studying the game's fundamentals like that college course you didn't attend lectures for and have to scramble some chaotic notes of someone else to try passing an exam.