I succeed on more problems than I fail, mostly pick good options yet my realm is troubled for some strange reason. :-/

There is some really good kingdom management post in steam:

https://steamcommunity.com/app/640820/discussions/0/1730963192539824644/

in general, you should always have enough BP left for wishes of your advisors. when your advisor comes to you and wants to have 100 BP and its not in your treasury, then you get a -1 in the general unrest. The rest of the unrest is, because via time, you need all the advisor areas (military, community, economy, etc) in some higher numbers. not just one, but all of them.

If you are not able to achive this, then your kingdom gets more and more unrest and you fail.
Some very short solution are this events you can buy for 1000 BP, which does improves the unrest +1, but as i said, if you have not upgraded the general numbers, you will get more and more unrest, until your kingdom fails.

In one of the last patches they included an option somewhere, that your kingdom cannot fail anymore. i have not checked it, yet.

Edit: the time, when most people are complaining about the rsining unrest failure is somwhen in 4713, so, in the third year of the game. you have to use the peace time in between the crisises to improve your kingdom. otherwise you do not have enough to handle the unrest.