The pronunciation Yahshua is philologically impossible in the original Hebrew and has support neither in archeological findings, such as the Dead Sea scrolls or inscriptions, nor in rabbinical texts as a form of Joshua.
In the 19th century, the Second Great Awakening led to a religious revival of Protestantism in America which spawned several divergent movements.
Part of a larger attitude to reorient Christianity to what was considered its Jewish roots, Adventism eventually gave rise to groups such as the Assemblies of Yahweh, which taught that the Tetragrammaton should be directly translated as Yahweh as opposed to the traditional translation of simply "LORD".
[8] However, the general consensus of Bible scholars is that the New Testament was originally written only in Koine Greek (save for a number of words); the claim of the Assemblies of Yahweh therefore received no traction in academia.
[14]Such arguments have been roundly rejected by academia in which the idea that the texts of the New Testament were translations from Hebrew or Aramaic got no traction.
[15] The pronunciation Yahshua likewise cannot be found with that spelling anywhere in history, in writings in Hebrew or otherwise, prior to the 1900s.
It didn't exist in biblical times and it has not existed as a genuine Hebrew name in history — until people who really didn't understand Hebrew made it up, thinking that it somehow restored the "Yah" element (from "Yahweh") into the Savior's name... there's no such either as Yahushua — Joshua was pronounced ye-ho-shu-ah.