my (limited) understanding of it is there were no vowels in Hebrew; thus the tetragrammaton, or YHWH / YHVH.
but identifying the true pronunciation is problematic. most scholars seem to agree it would be "Yahweh", but there is some dispute, as you say, and it's certainly not definite. i tried to study it once but i think i need to know more about the Hebrew language itself to fully understand.
Jews i've known are much more careful with God's Name than Messianic Christians, though i couldn't tell you if that's coming from respect, fear, or tradition.
(i don't even know my own heart, let alone that of someone else! lol)
They didnt respect the Creators name, they caused it to be forgotten:
Yeremyah 23:26-27, "How long will this be in the heart of the prophets who prophesy lies? Yes, they are prophets of the deceit of their own minds plan and scheme,
to cause My people to forget My Name through their dreams, which they tell every man to his neighbor, just as their fathers have forgotten My Name for Baal."
Talmud - Mas. Sotah 38a
Another [Baraitha] taught: ‘On this wise ye shall bless the children of Israel’ —
with the use of the Shem Hameforash.15 You say that it means with the Tetragrammaton; (Yahweh) but perhaps that is not so and a substituted name was used!16 There is a text to say: So shall they put My name17 — My name which is unique to Me. It is possible to think that [the Shem Hameforash was also used] in places outside the Temple; but it is stated here, ‘So shall they put My name’ and elsewhere it is stated: To put His name there18 — as in this latter passage it denotes in the Temple so also in the former passage it denotes in the Temple. R. Joshiah says: [This deduction] is unnecessary; behold it states: In every place where I cause My name to be remembered I will come unto thee.19 Can it enter your mind that every place is intended?20 But the text must be transposed thus: In every place where I will come unto thee and bless thee will I cause My name to be remembered; and where will I come unto thee and bless thee? In the Temple; there, in the Temple, will I cause My name to be remembered. Another [Baraitha] teaches: ‘On this wise ye shall bless the children of Israel’ — I have here only the children of Israel; whence is it that proselytes, women and enfranchised slaves [are included]? There is a text to state, Ye shall say unto them21 — i.e., to all of them.
"but perhaps that is not so and a substituted name was used,"
No Scripture says anything like this at all, a Rabbi comes along and says, " "but perhaps that is not so," and after that Yahweh's Name is hidden. However it is not that FOOLISH and innocent, as it was on purpose that this was contrived:
Talmud - Mas. Yoma 39b
His brethren [that year]
the priests forbore to mention the Ineffable Name (Yahweh) in pronouncing the [priestly] blessing.4 Our Rabbis taught: During the last forty years before the destruction of the Temple the lot [‘For the Lord’] did not come up in the right hand; nor did the crimson-coloured strap become white/"