I lean towards a belief in God, but used to be agnostic. What clinches it for me was not the question of whether or not God exists, but that there exists an inate God-shaped hole in so many people's hearts which ... must be filled with something. Even if it's only a placebo effect, a kind and just God who insists on love and fairness is a damn sight better than oh, say, objectivism or capitalism or anything else that can be used and twisted by those in power to assert their unjust advantage.
A belief in God may not make all men good, but it keeps the honest honest, and provides a necessary outrage against exploitative acts through shared voices: An army of righteousness, so to speak. It is no accident where that God arose in so many different places during the Axial age, when it was finally possible for some to accumulate significant wealth and power and control in that period.
While an individual standard of morality may be all well and good, but as they saying goes, we either hang together, or we all hang seperately - posting a tweet is a singular act, but joining together in religion creates both community and power. The world we live in drives so many of us to stand alone whether by choice or by corporate and political manipulation or accident of technology, so only something as big as God or a renewed sense of democracy and freedom and social justice can drive these forces back. Concepts and beliefs that cut across so many boundaries are quite rare, and so must be cherished.
One might also say that God does not interfere, that God allows evil and so many other things because God (if he exists) is remote and non-responsive. This is true, and one might say that God allows free will, that God is merely a watchmaker who creates and does not intervene, etc. But consider, if God is only an invention to lay down a common set of behaviors and morality across all boundaries, then this very distance from earthly humanity protects God from being redefined by those with the means and power to twist the interpretation of God to their own advantage. It protects the God concept, and the God concept protects us. It must remain aloof to be safe, for us to be safe.
If God is real, it only proves religion as a test of faith. If everyone was sure God was there and watching and real because he makes himself known in blatant forms, then, well, you should be able to fill in the dots on that one. Faith is an invitation to the afterlife (if this is all real), but if you're a jerk you don't get the invitation, or in common Christian thinking, everyone gets an invite, but if you toss it out in the trash you won't get pass the door guard. The afterlife is God's party after all (if any of this exists). This presupposes of course, that life is temporary and not worth the bother, and that it is the eternal afterlife wich is what matters. Cold comfort in my book but... meh.
I can think of three systems which rejected God and then filled it with their own over-arching principles: the French Revolution, Communism, and Nazism, all of which led to the deaths of millions and misery far beyond even that scale in great number. It may only be a coincidence, or a consequence of intentional acts by a few to sieze power, but breaking something that is maybe only somewhat broken seems to have significant consequence when it comes to principles of morality. At the very least it tends to create bad moments in history.
TL;DNR I don't know if God exists, but for entirely practical reasons we are weaker without him, because a belief in God has historically (at its best) created communities across political, racial, and all other artificial boundaries, the very boundaries exploited by the malicious to keep us separate, alone, and vulnerable.
(Apoligies for non-gender, etc diversity above: of course I also mean women, and he/she/it for God's nature and ... sorry, not up on the muliple gender lingo but that too, but it just reads more poeticly using the archaec pre-"woke" usage. No intentional exclusion was meant).