First, let’s analyse the meaning/definition of each word ‘religion’ and ‘secularism’.
According to the Cambridge English Dictionary, the definition of religion is:
“The belief in and worship of a God or Gods, or any such system of belief and worship.”
According to the Merriam-Webster, the definition of secularism is:
“Rejection of religion and religious considerations.”
As you can see, secularism and religion are opposite of each other. Like the day and night. So it is clear that it is not possible to have a secular religion.