There is more to religion than doctrines, and much more to understanding religion than just understanding doctrines; but if the doctrines of a given religion are false, or if there is no good reason to believe they are true, then such a religion is not a live option for me.
Admittedly, some religions are less doctrinal than others, but I have found no religion which did not incorporate - as central elements - ideas which I find utterly implausible. Even Buddhism - often presented in the West as being open to a scientific understanding of the world - is committed, like other religions, to the idea of an objective moral realm, and also (at least in its Tibetan form as articulated by the Dalai Lama) to the notion of the soul as spirit, not entirely reducible to the self as understood by science.
Many people, reluctant to give up on religion entirely, admit that the doctrines they may have once believed are indeed false, but argue that there is a central core which the major religions share, a kind of essence of religious truth. When pressed to say what this core consists in, what exactly they do believe, such people reply in various ways, some more plausible than others. But I have never heard or read an account that attracts me or that I could personally endorse or adopt. For example, it's all very well to say that our minds have inbuilt limits. Of course they do, but does this fact suggest that something like what religions envisage lies beyond those limits? Often it's asserted that there is a benign force underlying reality: the evidence, I would suggest, is overwhelmingly to the contrary. Or that all is one, all is interconnected. I agree, and there is some evidence for this in physics (e.g. quantum entanglement) but how is this idea a religious one?
Religion, of course, is a very personal thing, and we all have our own deep reasons or motives for accepting or rejecting religious claims. I was a Christian until my early twenties when, one night, I suddenly realized that the burden of proof was on those who sought to affirm the claims of Christian doctrine rather than on those who sought to deny them. I say 'suddenly', but this shift in perspective happened at a time when I had been reading a lot of historical material on the Jewish background of the New Testament, and realizing that so much that seemed so special in the figure of Jesus was explicable historically. For a few weeks, I toyed with the idea of adopting the Jewish faith (as Christianity minus Jesus seemed to equal Judaism), but I found the notion of a 'chosen people' a little hard to swallow. And the notion of a personal God seemed more and more unreal. I had accepted it as part of a package of beliefs. But without those other beliefs (about God acting in history or through particular individuals or institutions), what reason was there to believe in such a being?