Theism (or more specifcally monotheism) is the recognition that something unexplainable is going to have to be used to explain reality. It can be beyond this universe like m-theory or beyond that. It can also be this universe itself (pantheism). This unexplainable thing is worthy of the title god.
This is my favorite definition of theism and my wording for it. There are a million different definitions for atheism so I made one for theism.
As far as Ravi goes I think you would like John Lennox. He has defeated Dawkins and every other atheist in debate. He also does lectures at schools and such as he is a professor at Oxford.
Here is one of my favorites of humilating Dawkins. https://www.youtube.com/watch?v=4NzFr4lM-lc
I like Ravi quite a lot. Learn something new every time I listen. Not familiar yet with Lennox.
What Ravi doesn't admit about Mormonism is the early appeal of Mormonism was specifically an appeal to literal interpretation of biblical text, which the christians of the day had sophisticized.. . .. for lack of a better term. . . . into the Trinity concept of ..... ha ha. . . . Monotheism. Mainstream mormonism made a sharp doctrinal turn in the early twentieth century, and joined the Trinitarian Mystery Cult that tries to make Jesus everything.
The original concept of Hebraic monotheism held the name of God sacred and indeed maintained one unchangeable and eternal God, the YHVH tetragrammaton person. .. . . definitely a person. . . .. because Abraham saw Him, and fed Him, on the plain of Mamre, and Moses is described as seeing the face of God and in other respects finding that God was of a person's form and substance. . . . though worthy of infinite respect for being a God of every form of virtue in perfection. David in Psalms 110 verse 4 says the Adonai or messianic figure of a saviour for Israel would sit at the right hand of God, clearly being a separate character...... not the YHVH one God. . . . . .The Hebrews did not expect the YHVH character to come dwell with them in mortal coil.
Paul said that Jesus was the "High Priest", or intercessor with the YHVH character.
So anyway, early Mormons knew there was one covenant maker with man, and a separate character being the intercessor or saviour or the lamb offered in atonement for our sin.
The Holy Ghost is only a gift of spirit, necessary in the service of believers only because GOD is indeed a person of human form. GOD is the same yesterday, today and forever. HE was a person of human form before this world was, when he made covenant with Abraham, and when he spoke from Heaven declaring Jesus to be his only begotten Son, and when HE appeared in the sacred Grove and introduced the Saviour to Joseph Smith.
Jesus is not that GOD, as he was a spirit until he was born into life in this world, and was mortal while in this world, and after being resurrected has been immortal. That is definitely not the same "yesterday, today, and forever".
So anyway, the tendency to make Jesus equivalent to GOD was evident in the New Testament, and is probably the best reason the Jews could have for disbelieving tha the Christians have the right belief in God.
But despite the failure of Ravi to research the issue in Mormonism, I think he does pretty good as an apologist for Christianity. Just not the fact that Mormons are not pretty good Monotheistic believers in the Hebrew God, the God of Abraham. Of course Mormons have always had freedom to talk off the top of their heads. . . . and not everyone has understood it very well, if anyone has at all. . . ..
But I think the Trinity is the most flagrant nonsense mankind could ever conjure up, and the early Mormon statement on the identity of the person YHVH the most clear-cut notion of monotheism at least in the Christian world.
and yes, the doctrine may have popped up in the "bible belt" of the American frontier as the consequence of folks reading their bibles more carefully, and being unsatisfied with traditional gobbledlygook Trinity hocus-pocus.
but it is what the Bible says, at least in one line of statements. . . . not to say there aren't plenty of confused writers in the Bible who wanted to make Jesus the GOD.