“God is the same yesterday, today, forever. If a thousand years is one day to God in the millennium, then it could be in Genesis, and obviously was.”
If you want us to accept this argument, then you’d have to apply it consistently. So, every time that the word “day” is used in the Bible, you must substitute “thousand years”. Otherwise, you are not following the first sentence, but actually claiming that God changes this principle whenever it’s convenient for your interpretation.
No, we study to know when a day is a day to us and when a day is a day to God:
2Ti 2:15 Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.