There is no religion. Dasam Granth Ji explains that the teachers of Hinduism and Islam became corrupts and became psychopaths, Mohammed circumcising his followers and the gods and goddesses were in ego making people worship them. Religion is false, there’s only the Pure Uncorrupted teachings that the Gurus taught. They added teachings of other bhagats who were born into other religions but who detached from them and practiced Truth, to show that religion is false. That Truth is One.
That’s why Guru Nanak says to replace the Hindu and Muslim rituals with truthful actions and deeds instead, because the rituals mean Nothing. There’s only One as taught in Guru Granth Sahib Ji. Many others twisted and corrupted Gods messages and fell off the path. The Gurus came at a time where there was so much darkness, falsehood and false rituals and religion. Guru Nanak eradicated the false constraints of religions, and taught us that there’s only One All Pervading God, One pervading Truth..no Hindu, no Muslim. How can God who is all pervading be constrained to anything..to any religion, caste, culture or sect. We have Punjabi’s who are buried six feet under in culture to the extent that they believe that white, black, Chinese, reds Indians are different from us, when humans are Equal, it’s the man made constraints of religion, culture, caste, false societal levels, wealth and poverty etc that blind us to the Truth. When you’re a Sikh, ie student of Truth, you don’t constrain yourself to an illusion. You free yourself of it and realise it’s all just God and hence become all loving and fearless, Nirboah and Nirvair.