I haven't studied religion but I've been in one and left it. Religion looks and feels so man made. The way people worship god feels like the way that a king would wish to be worshipped by people. The morals that god has feels so human like too as I can imagine humans in power having the mindset of "believe and worship in me or suffer for all eternity in hell". The concept of heaven and hell feel so human like too with both of them being described as eternal happiness and eternal pain respectively. Many people can't comprehend just how massive infinity actually is yet use this as a way to make it sound serious. The concept of a god punishing the evil people and rewarding the good people is human like too as every human wishes that justice such as this were to actually exist (and hence find solace in religion due to this).
The concept of filling god in every point that didn't make sense at the time just to have an answer (i.e. "god of the gaps") is human like too. The teachings of the religion clearly mirrors what humans at the time thought about things (such as hating LGBT people, the scientific knowledge they had access to at the time and so forth).
On top of religion resembling human like behaviours, it also seems clear to me that religion is invented by humans for humans. For one, the idea of a god existing that, in all of his power and knowledge, cares about puny humans like us makes people feel good due to their ego acting up. Also, like I already mentioned, the idea of god delivering absolute justice to make up for the justice during life that didn't occur makes people feel good too
It's hard to even entertain the point that religions are true due to how human like they obviously are. It's definitely made by humans for humans