So I'm a Christian and a developer that retains faith - so I can answer you from a sample size of one.
My faith comes from prolonged personal encounter with Christ, not the acceptance of some dry set of creeds.
Yes, it's mystical.
Yes, it is non-rational - in the strict definition that it depends on things that can be experienced and known spiritually, but that can't be explained through reason.
So after coming to faith as an atheist the Bible didn't make much sense: the gospels sort of made sense, especially John and the letters weren't too bad.
They were describing Someone who matched my experiences.
The prophets were just plain trippy, the old covenant rituals confusing and weird, the history more than a bit unclear.
So over the years that has clarified a lot. Spending time asking Him what was up with all of this has resulted in personal answers.
The rituals are a kind of children's Bible - a symbolic pictorial language that explains things that aren't easy to project to where we live otherwise.
Prophecy is a rich set of symbols - Western thought is quite limited in its ability to express some kinds of thinking.
After spending time with mnemonic systems I've come to recognize how some of these techniques match the grain of the human mind much better that
a textbook approach.
I've come to appreciate its structure and perfection.
Many fail to parse it, partly because parsing it requires non-reason processes, but when it has been parsed it is reasonable.
This might not be very convincing and I lack the bandwidth to explain much in a comment, but it has a unifying superstructure:
It starts with "in the beginning" and ends with "amen".
Like verse it starts with the themes: creation, the marriage of the first man, the fall induced by the serpent and then ends with the fall of Satan, the marriage of the Lamb and then the new creation.
It's macro structure is:
A beginning,
Three sections: a covenant, history of the covenant,
writings about a covenant,
Then a repeat of three sections for a new covenant.
Then an ending.
This is the same logical structure in outline of the first 7 day (period) creation scheme.
A start, three days of creation, three days of infilling and a final closing day.
Internally these sections have cross-references that match the structure.
These structures are preserved across multiple human authors, across millennia.
It is actually a good guide in contemporary life - as a simplifying assumption you can only look at instructions given in the letters, since these match the age we are currently in.
As a second parse for instructions, look at the Proverbs, which are mostly universal principles.
Instructions given to other peoples and for other times are interesting and give insight into God's principles, but aren't directly applicable.
But in the end the book is useless to you without the Author. Approach Him first.
If you approach Him through the Bible, I'd recommend starting with John and the Acts and the letters - and then trying to ask Him to open it up further.