I'm in the same boat, although at a bit of a different angle. My biggest problem was that it was just as pointless as atheism (from the perspective of being religious), and infinitely more pointless (from the perspective of being atheist). God creates us, we choose sides (heaven or hell) by our actions, we die, we go to heaven or hell... and then what? God has simply sorted us into two boxes, neither of which has a purpose, and worse, he's put one group of us in a box to torture for the simple reason that he doesn't want the people in that box.
The big problem with this is always the same: once we're all sorted, what's the plan? You've gone to all this effort to extract the most desirable humans from the entire human population for all time... for what?
And of course, nobody has an answer for this. once the last prophecy of any holy book is completed, once the end-all battle of good vs evil happens, once evil is thrown back into hell... then what? do we all just hang around for all eternity, twiddling our thumbs and making small talk?
because the nature and the violent world amazed people who lived from the past and they cannot explain how all began---they invented creator...