Yes, Opal we know how the letter shin was pronounced in Biblical Hebrew. Haven't you heard of Shibboleth? The Ephraimites like the New Testament Greeks would pronounce it with the incorrect ''s'' sound - ''Then Jephthah gathered all the men of Gilead and fought with Ephraim. And the men of Gilead struck Ephraim, because they said, “You are fugitives of Ephraim, you Gileadites, in the midst of Ephraim and Manasseh.” And the Gileadites captured the fords of the Jordan against the Ephraimites. And when any of the fugitives of Ephraim said, “Let me go over,” the men of Gilead said to him, “Are you an Ephraimite?” When he said, “No,” they said to him, “Then say Shibboleth,” and he said, “Sibboleth,” for he could not pronounce it right. Then they seized him and slaughtered him at the fords of the Jordan. At that time 42,000 of the Ephraimites fell.'' Judges 12:4-6 ESV
That answers your question does it matter how exactly one pronounces a single letter.
When Jesus returns, he will give a pure tongue to his faithful remnant, and they will be able to pronounce everything correctly - Zephaniah 3:9.
YHVH isn't the universe. His name means ''he who will be, he who is and he who was''. The universe has a beginning according to the Bible, while according to science, it has both a beginning and an end*. The creator neither has a beginning nor an end. He is the everlasting God - Isaiah 40:28, there is no god before him, nor will there be another god after him - Isaiah 43:10.
*
https://www.astrologyweekly.com/forum/showpost.php?p=1055802&postcount=1170
https://www.astrologyweekly.com/forum/showpost.php?p=1059222&postcount=1352