The best method seems to be holy texts from so long ago that the origins are hazy at best. It’s one reason it’s hard to believe that Mormonism took off so well; Joseph Smith’s personal foibles are still well recorded.

For baseline Christianity (not Mormonism), there are a number of works giving a defense of the holy texts as being historically accurate. "Evidence That Demands A Verdict" by Josh McDowell was a good one, but it is almost certainly out of date by now. "Cold Case Christianity" by J. Warner Wallace is a more recent one, but is far less comprehensive.

From a philosophical perspective, "He Is There And He Is Not Silent" by Francis Schaeffer is solid. It's simple, but very deep.

Historically they may track somewhat with the evidence, but I’ve seen no signs of the god or miracles they claim existed in that time.

Joseph Smith never claimed to be perfect, and notably said he was not, but that "there is no error in the revelations." I have learned for myself that the Book of Mormon is true (and amazing), and so can anyone who wants to test it for themselves. (More at my web site--in profile, nothing for sale, no stylistic ambition.)

(Smith's life is thoroughly, unflinchingly documented: https://www.josephsmithpapers.org/ ).

(Thoughtful comments appreciated with any downvotes.)