That;s the thing, the human body isn’t all that great, it’s a kludgy mess of ad hoc exaptations with a genome full of junk. Precisely what you’d expect from a blind process and not from an infallible creator.
Depending on how you understand the theology. According to the biblical context. The world is
fallen, but despite all that - the "simple" cell...is remarkably not so simple at all.
So?
Anyone who thinks cells are "simple" must be simple themselves.
Back in the '80s, my Molecular Cell Biology textbook (I think it was imaginitively entitled "Molecular Cell Biology", or something similar) was the size of a telephone directory (remember those?), and was just a basic undergraduate primer on the broad topics.
Biology has been described as "complex chemistry", and given the difference in scale between molecules and cells, you can fit a shitload (if you will forgive my use of a technical term) of chemistry into a cell.
A large protein, such as a haemoglobin complex, masses about 64,000 Daltons, which is about 10
-19g. A red blood cell (one of the smaller and simpler mammalian cells) masses about 3x10
-11g, so about 300,000,000 times as much.
Three hundred million molecules is a lot (but is a very significant
underestimate of the number of molecules in a red blood cell, which are mostly water molecules massing around 18 Daltons, or about one 4,000th of the mass of a haemoglobin molecule).
A good ballpark guesstimate would be that there are in the order of between one hundred and five hundred
billion molecules, of a bewildering variety of types and sizes, in any given cell (and even more in the larger cells, of course) - all interacting dynamically with each other and with the outside world, in highly complex ways.
That's your "simple cell", right there. About ten times as many molecular interactions as there are humans on Earth.