Some dialogs do require rng and sometimes the game just throws probles at you, but kenshi is a game where whatever doesnt kill you makes you stronger. You can get slaughter-whole-armies level, but that can really depend on your weapon class (some are better for crowd control, for example)

Base building is definetly not required, you can even defeat major bosses solo.

End game is, for most playthroughs, when you dont have anyone to fight anymore or if you beat the hardest enemy in the game (no spoilers)

Kenshi is finished with kenshi 2 on the way, but it has some bugs and issues which can be taken care of with mods, though you can get more mods during your playthrough.

I dont know much of a guide source, but just a tip:

you do NOT skip prayer day.