Yep. In California, we were explicitly instructed to not consider the value/meaning/reliability/etc of testimony until deliberations had started. You’re not supposed to let some testimony prejudge against other testimony. Ideal jurors are perfect sponges of the testimony who then make perfect decisions based on the whole gestalt.
Definitely not a good system, but like democracy, it’s better than the alternatives.
In my jurisdiction, the record is an audio recording, not a physical transcript. When the jury wants to review the testimony, the court clerk brings up the appropriate spot on the recording and plays it back, so they hear the testimony and the questions just as they occurred.
They may or may not be told by the judge, (depending on jurisdiction) but they are given an overview of the case, and in opening statements both side usually hit what they intend to prove/what the other side will be unable to prove, so the jury is oriented to the crux of the dispute.
For example, I may not tell the jury the five elements of possession of stolen property, but I could outline the fact that my client was 10 feet away from the glass bowl when the police came in and his fingerprints were not on it when it was tested.
In my jurisdiction there are no read backs of testimony. You have to remember it live. I’m sort of divided on the rule. I like it when damaging testimony is not read back. I hate it when it is favorable testimony.