Crusader Kings III

It has taken me several years to like and get into Crusader Kings 3. It's a complicated & intriguing game which always left me cold when my ruler died - as your precious realm is split apart by partition.
Recently I found a historical focused youtube series by 'Realm Builder Guy' (I highly recommend) who introduced me to the 'secret' of enjoying Crusader Kings:
You are not there to build & defend a nation (a modern concept). Your role is to further your noble House influence and legacy, to bring stability and prosperity to your lands. CK3 is about Dynasty, not empire.
When I stopped trying to power-game the system, stopped frantically acquiring territory in a race to make a larger Kingdom, stopped making stress decisions 'out-of-character' for an advantage, the game started to click with me. Instead of jumping in trying to manage an entire Kingdom, I chose a humble English Earl in 1066 and spent 40 years tending to my family, my faith and the needs of my people. The Pope granted us several Duchies from the heathens in Wales and suddenly we were a Duke. I had rivals, friends and a benign King who I served faithfully. It was completely absorbing.
So that's my main advice for new players; ignore the huge kingdoms and the Irish tutorial, play someone small and navigate that persons life. Don't sweat your realm splitting up on death, focus on the wider picture of your House glory and the long game becomes much more compelling.
- Signed, your faithful servant Duke Cato of Powys, Defender of the Faith and Guardian of Warwick.

I wrote a love letter to the pope.
I murdered my own uncle for making fun of me at a feast.
I slept with my sister.
I then sat down to play some Crusader Kings 3, it's a pretty good game.

I bought this game upon recommendation of a friend of mine. I never really played other Paradox titles before except for a little bit of Cities: Skylines. I'll be honest: I did not get this game at all when I first started. It felt overwhelming and I was sort of just clicking on things. I mostly started by playing with my friend so I could ask questions along the way. I had small victories here and there, but I still never truly understood the game.
One day I boot up the game and decide to give it another go. I won't lie—I was determined and did some prep. I watched a few CK3 YouTube videos before I embarked on this journey and read a little bit about strategy (seriously, shout out to Snap Strategy for turning this game into digestible content). I started out as a mere Duke and spent time to think before I made decisions. I thoroughly read the in-game pop-ups for words or phrases that I didn't understand. (The UI helps explain a concept if you just hover over the word with your cursor.)
My Duke had a son, he became a King. Descendant after descendant, my realm's economy grew more and more. Eventually, I was able to successfully bribe anyone that stood in my way. Before I knew it, it was 3AM and I was elected Holy Roman Emperor due to my economic power, prestige, and bribery. With one click of a button, I revoked the election laws of the Holy Roman Empire. Yeah, I had some resistance from my important vassals and not so loyal subjects. These are problems that can be fixed with money or an excellent spymaster. I was at my peak. I worked my way from a lowly Duke to become the Holy Roman Emperor, flush with cash. Until I wasn't.
You see, as I alluded to earlier, you play as an individual ruler in this game—not an entire country or kingdom. When you die, you play as your heir. Well... if no one likes the heir, or if the heir is incompetent, then empires can crumble. This can sometimes be "fixed" by changing your succession laws, disinherison, or killing them (yes, killing your son/daughter—this game can be brutal). I had one son, took a gamble, and I died a little too soon. So be it. My empire crumbled because my heir was an idiot that nobody liked and neighboring conquests came knocking on my door. When it was all said and done, the Holy Roman Empire dissolved. I was broke, incompetent, inbred, had no allies, and owned a tiny tract of land hundreds of miles from my original realm. But holy hell what a fantastic ride it was straight to the top and a plummet to the bottom.
I started to "get it" after that playthrough. The replay value is insane and I will be playing more. I really respect the hell out of this game. CK3 can be punishing, but oh man can it be so rewarding too. It will be overwhelming when you first start this game. It can also be a time commitment. But I absolutely recommend you give it a chance—or two—or three. Be curious, read stuff, and follow the game's advice when it tells you to do something. It is a good time.

Played my first game, had my wife and heir Kidnapped by vikings. My heir was tortured until he died of stress and my wife was forcibly made a concubine.
I spent 20 years single, building up my power until I could finally free her and remarry. She died not long after and I thought I'd play out the rest of my characters life until he died, and restart.
As it turned out I found a "wolf-boy" whilst I was on a hunting trip and was offered the chance to raise him, and make him my heir. When I died he went on to not only found his own Kingdom, but an empire when he was 60.
This game is epic, and my only complaint is that I didn't play it years ago.

I've played over 300 hours and still don't know how the game works.

I stared at a map for 100 hours
EDIT: It's 222 hours now

Sacrificed the pope to odin and was immediately killed by 50,000 catholic troops. 10/10