Light was created before the sun, evening and morning were before the sun, and there is no difference in the treatment of evening/morning or day counting after the sun.
There is no doubt creation was easy for God, impossibly complicated for us. Nevertheless, if he could create everything in 14 Billion years using evolution, he could do it in 6 days. It's all miraculous, why doubt His record of it? What possible benefit does one gain compromising scripture with the "science" of macro evolution. Perhaps to convince the skeptic? The thinking skeptic, who may consider Christianity may notice the supposed inconsistency in interpretive uncertainty of Genesis, but the "certainty" that Jesus is the only way.
Either the Bible is the Word, or it's not. Once we start the slippery slope of "The Bible CONTAINS the word of God", and we have to determine what is inspired, and what is not... That's exactly how we get homosexual ministers! Satan always mixes a little error with truth, and gets us to doubt God's word. Consider his question to Eve, "Did God really say...", and then Eve started adding to the Word "...and we can't touch it". This whole discussion is exactly the same, if you think about it.
The point is, how to speak about “solar days” if there’s no sun yet? There was light called day, darkness called night, evening, and morning, day one. But there was no sun. ¿What was a day, then? ¿What we call “a day”, the setting and rise of sun? ¿Which sun? It makes no conflict, then, to assume “day” can mean something different here. It could be that we are wrong on thinking that our current definition of day is the best and most complete one.