where does today Quran variants like khalaf, hafs, warsh, etc... come from? do they go back to the prophet(pbuh) and it's the different way the Quran was originally revealed with or they go back to Uthman(ra) Quran as Uthman(ra) burned those different variants and these different came to place where Arabic diacritical marks had to be added to the Quran?
Quran was revealed in 7 ahruf and 10 Qira'at to prophet muhammad(PBUH). THIS IS Because of the fact that different people have different ascent or dialects and different way to pronounce words. EXAMPLE: https://dictionary.cambridge.org/pronunciation/english/privacy 7 ahruf was revealed to make 7 Arab tribes -(Quraysh, Hudhayl, Tameem, Hawaazin, Thaqeef, Kinaanah and Yemen), easy to understand Quran and leave no room for doubt.
The differences between the canonical qira'at (and the accepted transmissions thereof) are supposed to be derived from authentic ahruf recited by the Prophet. The canonical readings are those that comply with the Uthmanic rasm (there were many others that did not), which had only sparse or no dotting to distinguish homographic consonants which can change a letter from one to another, nor short vowel marks which affect grammar. The variants also involve far more than dialect differences. Each of the seven or ten canonical readers is supposed to have picked from authentic options passed down to him (as well as having his own general recitation rules, or usul) and after some centuries they were considered fully authentic. Of course, the details are more questionable and even some early scholars and grammarians criticised things now recited as Quran before the consensus emerged. There is still disagreement on the nature of the ahruf and some other questions. The following site has a good Resources page listing ways that you can see the variants in English, Arabic and transliteration, useful academic papers and books etc. https://quranvariants.wordpress.com