Due to the inherent difficulties in bible interpretation, that particular activity within the Christian religion has always been accessible predominantly by the elite. Laypeople merely get told by their pastors what to believe about what the bible is saying (especially where it matters most, regarding doctrines, theology, moral principles, etc.). In turn, those pastors, depending on their training, can manage to be marginally more discerning in deciding which bible scholars / theologians to listen to, but often it looks like they just listen to / teach from whichever denomination they happen to find themselves in.
I think many Christians have been fed a lie that the bible is supposed to somehow be a magical book from which they can draw irrefutable truths simply by reading it. (As we have observed by the fact that bible experts themselves disagree on all kinds of theological points / doctrines that are commonly regarded as “essential” to Christianity.)
I think people need to stop treating bible reading like maths, as though you just need to add 1 + 1 = 2 to get an answer. Because the bible is actually more like x + y = ?, where there are many unknowns, so that what answer you get depends on what values you decide to assign to each unknown parameter.
Instead, bible reading should be more like a physics experiment. Different ways of reading the bible (assigning different values to those unknowns) generate different kinds of theories / perspectives, and in order to distinguish those that are true / false, we have to test those theories / perspectives in the real world, in our daily lives, etc. (E.g. is the command to pluck out our eye if it causes us to sin, to be obeyed literally or figuratively? Easy, pluck out your eye and see if it helps. It doesn’t? Okay, maybe taking it literally wasn’t such a good idea after all.)
The funny thing is “Christians” are often too busy obsessing over highfalutin / pretentious / elaborate theologies / doctrines that are completely untestable in the real world. Hence it just degenerates into a free-for-all sh*tfest where people just make up their own untestable assumptions which then generates all kinds of unnecessary doctrines. Unfortunately, most “Christians” are blind to the fact that their strongly held beliefs are really the product of arbitrary assumptions.
To actually answer your question, I think Christianity can begin from being as simple as simply obeying the golden rule, to as sophisticated as that which an individual’s knowledge / understanding can afford.
It becomes a problem when people with inadequate knowledge / understanding do not have the basic intellectual awareness / humility to acknowledge that, and go around teaching / preaching / professing belief in all kinds of doctrines / ideas that they cannot possibly prove to be true.