Firstly, if you think there’s a contradiction in Genesis between God creating plants before man in chapter one and then in chapter two the story focusing in on God creating Adam and putting him in a specific place then planting a garden in that specific place for him to work, then you’re just looking for problems.
Regarding the word “firmament”: linguistics has a lot to say about the way we describe the world, and how much or whether that reflects what we abstractly think the world to be. There is not always a one to one relationship there, and it’s a significant assumption to say that there is.
It is not necessarily the case that the Hebrews actually thought the sky was a solid, beat-out metal dome, just because they described it as such. That conclusion involves unjustified assumptions about the way language works.
Therefore, if we take the creation account of Genesis 1-3 ‘literally’ (which we should), we are not cornered into taking ‘literally’ the description of the sky as a solid, beat-out metal dome. That’s not how language works.