Hearts of Iron IV

No matter what I do, what I try, what DLC I buy, I just can't seem to understand this game. I even had one of my friends teach me how to play, He watched and told me how to do various things. After near 200 grueling hours in this game I just can't seem to understand it. The main problem is I dump so many hours building up a save to around when WW2 starts, and then just lose it all due to some mistake I made in like '38 or some ♥♥♥♥♥♥♥♥. It's an incredibly unfun experience. And I really Don't understand how it gets such a cult following. I've done so many things to try and like this game. I wish I could honestly get my money back. I try to play as germany, blitz through europe, then get overwhelmed by the soviets, So i decide to try out the soviets, Build up the whole game for when Germany comes knocking on my border and despite All my preparations I forgot to build the forts on our border which led to literally everything I've trained just being annihilated and the loss of like a 6 hour save. I wish there was like a tutorial or something that would like help me understand it better. I've tried videos, peers, online discussions and it just doesnt click. Leading to an incredibly unfun, and infuriating experience. Another thing is I genuinely hate how horrible the frontlines system is in the game. Its clunky, and borderline confusing at best. When you start to lose your frontline it just crumbles very fast because of how near braindead the ai for reinforcing tiles is.