We're on the third round, and no scripture is referenced nor recorded historical account has been given?
Do you believe the 69 weeks are literally 483 days or 483 years?
483 years. Decrees were given in Ezra and Nehemiah and the Israelites clearly returned to rebuild lol. Ezra returned in 457BC to restore proper worship. 483 years later brings you to 26 AD, the year Jesus was baptized and was recognized as the long-awaited Messiah.
(Remember Dan 9:25, 69 weeks until Messiah)
Jn 1
26 John answered them, “I baptize [only] in water, but among you there stands One whom you do not recognize
and of whom you know nothing. 27 It is He [the preeminent One] who comes after me, the strap of whose sandal I am not worthy to untie [even as His slave].” 28 These things occurred in Bethany across the Jordan [at the Jordan River crossing], where John was baptizing.
29 The next day he saw Jesus coming to him and said, “Look! The Lamb of God who takes away the sin of the world! 30 This is He on behalf of whom I said, ‘After me comes a Man who has a higher rank than I
and has priority over me, for He existed before me.’
31 I did not recognize Him [as the Messiah]; but I came baptizing in water so that He would be [publicly] revealed to Israel.” 32 John gave [further] evidence [testifying officially for the record, with validity and relevance], saying, “I have seen the Spirit descending as a dove out of heaven, and He remained upon Him. 33
I did not recognize Him [as the Messiah], but He who sent me to baptize in water said to me, ‘He upon whom you see the Spirit descend and remain, this One is He who baptizes with the Holy Spirit.’ 34 I myself have [actually] seen [that happen], and my testimony is that this is the Son of God!”
If days when did this 483 days of building start, no mention of this is in scripture prior to 33AD Calvary?
Clearly not future days as Jesus has already come and Atoned for sin.
24 “Seventy weeks [of years, or 490 years] have been decreed for your people and for your holy city (Jerusalem), to finish the transgression, to make an end of sins,
to make atonement (reconciliation) for wickedness, to bring in everlasting righteousness (right-standing with God), to seal up vision and prophecy
and prophet, and to anoint the Most Holy
Place. 25 So you are to know and understand that from the issuance of the command to restore and rebuild Jerusalem until [the coming of] the Messiah (the Anointed One), the Prince,
there will be seven weeks [of years] and sixty-two weeks [of years]; it will be built again, with [a city] plaza and moat, even in times of trouble.
70 weeks for all those points, proving they were all fulfilled in the 70th week when Jesus arrived as Messiah after the 69 weeks.