God knows everything about us, He created us and gave us life, we should absolutely devote our lives to honor Him. If God were dead (He's alive!) then there would be no reason to worship anything/anybody. We need to worship Him because He has given us grace to wash away our every sin.
Your conclusion that to worship a transcendent tyrant who endorses genocide, slavery, torture, rape etc. A god who is capricious, violent, and jealous, as well as frankly sadomasochistic in saying, I love you, but if you do not worship me, you will suffer for all eternity. That to me, does not sound merciful, or indeed characteristic of a god who claims to love all.
To make reference to my beloved Orwell in using his "thoughtcrime" concept, as something that God punishes with damnation, I think that god is, for lack of a better word, evil.
It is understandable that one would want to devote themselves to God and all that is associated with like why we are here and life and death issues. That said the focus should not be just on God but helping the poor, visiting the sick, clothing the naked and loving one's neighbour. This gets a lot of attention in the Bible and should get more from religious people.
Devoting one's self to "God" is living a deluded life...God does not exist...If he existed, there wouldn't be violence and war and people raping others and poverty and corrupt individuals...Also, in the bible, he is admitted to being a jealous God...Nobody likes a jealous person, never mind a jealous God...
You may argue "But you can't prove that he doesn't exist, can you?" Well no I cannot, but I think of it like this. Criminals are always "innocent until proven guilty" right? So I think that god is "non existent until proven real."
Because this is the way that I see things, I would never devote my life, or recommend that anyone does devote their life to someone that probably doesn't even exist.