Sneak preview of that coming post:
You can view other humans as noisy instruments, with many even being deliberately hostile jammers.
The engineering way to deal with noise is to statistically average many measurements.
With enough of them you can know the truth despite 99% noise.

Because of the huge number of copies and quotes from copies and arguments about quotes from copies during the first few centuries we have a high level of confidence that we have reconstructed the Biblical signal from the noise of human error and deceit.
On top of that, the Bible is massively redundant. All the important concepts of Christian doctrine are covered over and over again in many ways.
People still argue about the fine points, but that is almost always because they choose to filter out content that disagrees with their pre-desired outcome.

For example, if you have the following noisy manuscripts, full of errors, do you have any doubt about what the original said?

The quick xrown fox jumped over the slithy toves.
The quick brown fxx jumped over the slithy toves.
The quick brown fox jumped xver the slithy toves not.
The xuick brown fox juxped over the slithy toves.
xhe quick brown fox jumped over the slithy doves.
The quick brxwn fox jumped over thx slithy xoves.

The truth is out there.