Again I recommend James H. Hutson's "The Founders on Religion, A Book of Quotations" as a good place to start. It alphabetizes the subjects. "Creeds" and "Ecumenicism" are good places to read. The various notable churches of the day (except for the Quakers) were attached to orthodox creeds and confessions.
There are some Bible believing evangelicals who belong to churches with orthodox creeds, but will say something like "I believe in the Trinity (and everything else my church teaches in their creeds) because the Bible teaches such." I think most orthodox Christians who believe in everything in their canon of Scripture don't see any contradiction between Scripture and creeds, but rather some kind of complementary support.
But the sentiment I observe is different. It's a sentiment that makes the believer want to confirm his religious conscience by examining scripture and using his reason and experience combined with a willingness to disregard the content of creeds and confessions of the church to which he belonged. And also a willingness to disregard traditionally held orthodox doctrines.
It was this method that produced Thomas Jefferson's and John Adams' unitarian heterodoxy. But others like Benjamin Rush, William Livingston, John Dickinson, and even John Jay (and arguably countless others) operated according to this method but ended up in different places. John Jay probably ended up closest to "orthodox Christianity" out of that list. But he still gave Council of Nicea short shift.
So for Benjamin Rush, this method didn't lead to as it did for Jefferson, J. Adams, and (probably) Franklin rejection of the Trinity (one could argue Franklin claimed to be agnostic on the doctrine; but I read the record as him throwing his lot in with the unitarians), but rather affirmation of the Trinity combined with rejection of eternal damnation, believing all would eventually be saved with the unsaved experiencing a long period of temporary punishment.
When one does a search for "Benjamin Rush" and "religion" the denominational affiliation that comes up is Presbyterian. At one time in his life, Rush admits to holding such Calvinistic convictions, but then notes he ditched it for Arminianism and then theological universalism. His logic was if Jesus died for all then all would eventually be saved. And he claimed the Bible supported his conclusion.
But this is what Rush had to say on creeds:
I have often lamented the Squeamishness of my [. . .] mind upon the subject of religious Creeds and modes of worship—But accustomed to think for myself in my profession, and encouraged to believe that my opinions and modes of practice are just, from the Success which has attended them even in the hands of their enemies, I have ventured to transfer the same Spirit of inquiry to Religion in which, if I have no followers, in my opinions (for I hold most of them secretly) I enjoy the Satisfaction of living in peace with my own Conscience, and what will surprise you not a little—in peace with all denominations of Christians, for while I refuse to be the slave of any Sect, I am the friend of them all. In a future letter I may perhaps give you my Creed. It differs materially from Dr Brown’s as expressed in his Religio medici. It is a compound of the orthodoxy & heterodoxy of most of our christian Churches.
-- To John Adams, April 5, 1808.