There is an irony in old Charlie Russell's choice of the name Watchtower. The metaphor of a literal watchtower was used from the start to illustrate the idea that the look-out at the top gets a panoramic view of the land to foresee events before they arrived, Russell and later "The org" being the only ones to have divine insight.
It never worked for them, they never got anything right, it was all complete rubbish; a fantasy.
A parable of being a JW is like someone born in a cave who never leaves it. An even better illustration for JWs is Plato's allegory of the cave. There are chained prisoners (JWs) who never see the daylight except dimly but are forced to look all the time at the wall at the end of the cave. Some distance behind them is a fire and between the fire and the backs of the prisoners, puppeteers come with shapes casting a shadow play on the end wall of what is purported to be the real world.
The prisoners had no reference to know or to deny reality because the shadows were their only experience of the world.
So my point Unsure, is that the fuzzy images given you from Bible stories are not the basis for making any real life decisions.
Who requires salvation? Only those who have had the concept of sin and the serpent drilled into their brain!
Why does the "Bible based" JW religion act like a cult? Because early Christianity was also a dumb cult, feeding off the gullible in the same way.
You ask "Is it enough to believe in a God" as if to get some hope. If you wish you can believe in anything and everything and if hope is all you want then that's the way forward for you. However if you want to be honest and live without false expectations then it's better to recognise that we all die and therefore we should live knowing that our life is very precious and should not to be wasted on supernatural fairy tales.