Immediately after the start of Laozi's Daodejing (道德 - not the modern meaning of virtue/morals, but Natural Order and Heavenly Mandate) we read the sentence

无名，天地之始；有名，万物之母

"Nameless is the beginning of the cosmos; named is the origin of all things"

and here lies the explanation of the Nameless God and YHWH, something that predates Judaism/Christianity, in fact predates the separation to east and west of the tribe which was the common cultural root of all modern humans. This tribe worshiped an abstract God that was everywhere and all powerful, but had no shape, no location and no name. The tribe's West Asian descendents, the Hebrews, later imposed religious rules of not representing God by any object/image and not taking His name in vain, while its East Asian descendents, the Chinese (more specifically Southern Chinese, genetically grouped with Pacific Islanders - the Northern Chinese are genetically grouped with Mongols, Manchus, Koreans, Tobetans, Eskimos, American Indians...) called it Heaven and decided emperors had its mandate, just as medieval European kings thought they ruled by the grace of God. Heaven, too, could not be represented by any simple object or image; it is not even a simple locality.

The Roman era Jewish author Josephus, who was captured by the general Vespasian in his "final solution" of the "Jewish problem" then became his confidant after making the prediction of his being proclaimed as the next Caesar, which soon became true when Nero was assassinated, explained that YHWH, which are four Hebrew consonants, actually represented four vowels, i-a-o-a, and that the name Adonai came from adding consonants d and n to make the name pronounceable. (note: in the diagram the writing goes from right to left - modern Hebrew is written left to right)

He was only slightly wrong: the Nameless God's name had five vowels：I-A-O-U-E, which is approximated by YAHOWEH, which is itself approximated in different circumstances by JAHOVEH or YAHWEH, which is then approximated by YHWH. The vowel I and consonant Y have the same sound, as do the vowel U and the consonant W; H is actually the sound of taking a breath, necessary before or after a long vowel, and it often gets inserted to separate two vowels, hence its appearance in YAHOWEH. (This also explains why H is often silent in English words like "honest" and some dialects do not pronounce H at all. Abraham's name was originally Abram, hinting that H and the Convenant doctrine were adopted at around the same time,))

The god is nameless because the initial Semetic/Phoenician/Hebrew alphabet had no vowels and could not write down IAOUE, but the Hebrews were able to write the consonants-only approximation of YHWH, on its own unpronounceable - the philosophical concept of the nameless God also became a linguistic one. It was later that the Greeks took some letters of the Phoenician alphabet that do not have equivalent sounds in Greek, and used them to represent vowels instead. This augmented alphabet was much more suitable for representing the oral language of the various Indo-European tribes, which use combinations of vowels and consonants, that it became standard in all of Europe, with Latin version in the west and Cyrillic version in the East. In contrast, the oral languages of ancient Egyptians, Sumerians and Chinese, based on individual syllables, were more suited for representation by ideograms, with the Chinese continuing to use such a system down to the present. The languages of the Astecs and Mayans appeared to be ideographic too. The Hebrews and other Westerners inherited the religious ideas of the Sumerians, but not their language.

This Sumerian/Ancient Chinese God, the origin of all things, came from nothing, because thing and nothing are the same; this is why the end is also the beginning. This idea, combined with snake-fertility worship (probably adopted from another tribe allied by marriage, a tribe that was more primitively pagan), produced the Uroboros serpent that swallows its own tail, so that begin meets end, birth equals death, thing meets nothing.

(BTW -  I am not a Taoist, nor the follower of any other religion. My interest in the topic is purely abstract - I am into everything so I am into nothing.)

为什么说上帝无名但是又有YHWH这个名字？耶和华源自iaoue，是祭司祈祷的呼声；文字发明先有子音当时还未有母音，iaoue无法写，所以神无名；和，华两声中h子音是由长声呼叫中吸一口气而来；古犹太人有文字后用YHWH写上帝名，后来希腊人发明母音字母后才有Yahweh和Jahoveh的写法；h  一直有个发不发音的问题；h 声音“可有可无“是有历史原因的。旧约神叫亚巴兰改名亚巴拉罕就是古犹太语言起初没有 h 音后来增加，同神名从耶娃(yawe)改成yahweh/yehovah 耶和华同时，原来神名是呼叫 IEOUA，长吟中间要乎吸一口气才能继续，这呼吸声后来发展成 h IEOUA 只有元音没有子音，而古 semite 语言没有母音字母，所以神名无法写，是无名之神，后来有了 h 再加上 y, w 等半子音字母写成 YHWH, 才能写神名