A natural reading of Gen 1:1 with it's immediate context is that it is part of the first day of creation
1 In the beginning, God created the heavens and the earth. 2 The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters.
3 And God said, “Let there be light,” and there was light. 4 And God saw that the light was good. And God separated the light from the darkness. 5 God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day. ESV
However, Gen 2:1 concludes the sixth day with:
1 Thus the heavens and the earth were finished, and all the host of them. 2 And on the seventh day God finished his work that he had done, and he rested on the seventh day from all his work that he had done. 3 So God blessed the seventh day and made it holy, because on it God rested from all his work that he had done in creation. ESV
Is there any strong reason to dismiss the idea that Gen 1:1 is intended to be a prologue, referring to the entire six days of creation, and also functions as a 'bookend' paired with Gen 2:1 to textually demarcate the six day period. I'd be especially interested to know if there is something in the Hebrew text that excludes this reading.