I especially appreciate your pointing out that it was Evangelicals, or the early version of Evangelicals, who insisted on separation of church and state.
"Madison was one of the first thinkers in colonial America to understand why church and state must be separated. His advocacy for this concept grew out of his own personal experiences in Virginia, where Anglicanism was the officially established creed and any attempt to spread another religion in public could lead to a jail term.
Early in 1774, Madison learned that several Baptist preachers were behind bars in a nearby county for public preaching. On Jan. 24, an enraged Madison wrote to his friend William Bradford in Philadelphia about the situation. "That diabolical Hell conceived principle of persecution rages among some and to their eternal Infamy the Clergy can furnish their quota of Imps for such business," Madison wrote. "This vexes me the most of any thing whatever. There are at this time in the adjacent County not less than 5 or 6 well meaning men in close Gaol [jail] for publishing their religious Sentiments which in the main are very orthodox. I have neither the patience to hear talk or think any thing relative to this matter, for I have squabbled and scolded abused and ridiculed so long about it, to so little purpose that I am without common patience. So I leave you to pity me and pray for Liberty of Conscience to revive among us."
. . . .
Madison soon had the opportunity to translate his anger into action. As a member of the Revolutionary Convention in Virginia in 1776, Madison sought to disestablish the Church of England in that state and secure passage of an amendment guaranteeing religious liberty to all. The attempt at disestablishment failed, but Madison's ideas on religious freedom were included in an "Article on Religion" that was adopted by the Convention. The statement held that religion can be "directed only by reason and conviction, not force or violence" and guaranteed to all "the free exercise of religion, according to the dictates of conscience."
Here Madison was responsible for a great leap forward in thinking. At the Revolutionary Convention, delegate George Mason had proposed an amendment guaranteeing "toleration" of all faiths. To Madison, this did not go far enough. He sought to expand religious liberty rights beyond mere toleration and argued for the "free exercise" of religion a concept that would later resurface in the First Amendment.
. . . .
https://www.au.org/church-state/march-2001-church-state/featured/james-madison-and-church-state-separation
That is a great article to read if you are interested in this topic. Especially true if you have Evangelical friends or family who argue that we are a "Christian nation." We are a nation of many faiths and no faith at all.