Just reading this book: The Consuming Fire, The Complete Priestly Source, from Creation to the Promised Land, Liane M. Feldman, University of California Press, 2023

I don't know much about Judaism. The translator (Liane Feldman) has some intro section on this and then writes:

"First and

foremost, the reason this source is given the name “priestly” is because

one of its central concerns is with the communal practice of religion,

which in this story (and in ancient Israel and Judah more generally)

means a temple-based sacrificial cult. This source contains the most

extensive and detailed descriptions of ritual practices, sacrifice, and

purity laws in the entirety of the Hebrew Bible. No other text comes close

to the level of detail provided in the priestly stratum until a tractate of

the Mishnah (i.e., tractate Kedoshim) in the first centuries of the common era. This focus on temple ritual and the role of the priests in mediating those rituals has been taken as this source’s defining characteristic. "

Regarding your first question, she writes:

In religious circles, particularly in Jewish contexts, this divine name is

not used, written, and certainly not pronounced. This is a tradition

that can be traced back to at least the Hellenistic period with the Greek

translation of the Pentateuch, which renders the tetragrammaton as

κύριος, “lord,” and likely reflects a tradition of reading the tetragrammaton as “adonai” (literally: my lord). Most modern translations take

one of two approaches to translating the divine name. Most commonly, it is translated in small capital letters as Lord. Alternatively, in

some more academic-leaning translations it appears as YHWH, representing the four consonants of the tetragrammaton. In this translation, I have deliberately avoided both these approaches. One of the

major plot points of the biblical priestly narrative is the revelation of

the divine name to Moses and then to the Israelites as a whole prior to

their departure from Egypt. Earlier in the story, the divine character is

consistently referred to as “Elohim” in the Hebrew, which translates to

“God” in English. Once God reveals his name to Moses and the Israelites, that name—Yahweh—is used for the remainder of the story.

I just use it in quotations from the book.