Despite the inability of atheists to see it, first, even though higher motives are required for a Christian to follow Christ, appeal to self-preservation is a legitimate means of salvific motivation, thus even in this life it is the threat of punishment which is the base motivation for many in many things.
But while this often may be effectual in bringing a souls to repentance, it is the love of Christ, in response to so great a salvation for so great a sinner at so great a cost, that is to most supremely motivate the believer.
"For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead:" "And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again." (2 Corinthians 5:14-15)
"We love him, because he first loved us." "If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen?" (1 John 4:19-20)
"Be ye therefore followers of God, as dear children;" "And walk in love, as Christ also hath loved us, and hath given himself for us an offering and a sacrifice to God for a sweetsmelling savour." (Ephesians 5:1-2)
"There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love." (1 John 4:18)
Second, God did not create man just to destroy Him, but to be the recipient of His grace and to respond to it, and thus to manifest what is good and evil. This requires that one be able to make choices, and with choices come consequences. And as man is eternal, so are the consequences, and what one does with the Truth given him, which is obeyed will lead to The Truth, Jesus Christ, reveals what he really loves, and where he will spend eternity.
Your post also touches on the issue of how there can be a good God yet suffering in the world, which issue is called Theodicy.
In which my proposals are that God could have,
1. made us (and angels) with no moral sense and or deprived us from the moral ability to respond to or choose good [morally insensible].
2. granted us free moral agency, but never have given us anything to choose between [negation of moral choices].
3. provided moral revelation and influences but always have moved us to do good, and never have allowed us to choose evil (such as make believing in God and choosing good so utterly compelling — like God appearing daily and doing miracles on demand, and preventing any seeming evidence to the contrary so that no man could attempt excuses [effective negation of any freedom to choose].
4. allowed us to do evil, but immediately reversed any effects [negation of moral consequences].
5. allowed us to do bad, but restricted us to a place where it would harm no one but ourselves [restriction of moral consequences].
6. allowed us to choose between good and evil, and to affect others by it, but not ultimately reward or punish us accordingly [negation of eternal moral consequences].
7. given us the ability to choose, and alternatives to chose from, and to face and overcome evil or be overcome by it, with the ability to effect others and things by our choices, and to exercise some reward or punishment in this life for morality, and ultimately reward or punishment us accordingly [pure justice].
8. in accordance with the above, except have manifested Himself in the flesh, and by Him to provide man a means of escaping the ultimate retribution of Divine justice, and instead receive unmerited eternal favor, at God’s own expense and credit, appropriated by a repentant obedient faith, in addition to the loss or gaining of certain rewards based on one’s quality of work as a child of God.
And conversely, eternal punish to varying degrees those whose response to God’s revelation manifested they want evil, while making the evil that man does to work for the good of those who want good, and who thus love God, who is good [justice maintained while mercy and grace given.
For God will judge every action, every thought, every falling short of His commandments and none who rely on their own merits will not be judged horrifically. The only recourse God gives is to believe that His Son, the Lord Jesus Christ, paid it all on your behalf and is your only plea.
That is the ultimate love, to pay for what another cannot afford and as a gift for which one cannot buy with money.