Well yes, we can... know for sure there are only 2 different dimensions of existence, because that is all that is written of in all of God's Word.
That seems like an argument from silence. That is, arguing that the lack of evidence is evidence. We probably know less than 1% about the realm(s) beyond our own. It seems a bit presumptuous to presume we understand how everything works and what all goes on.
Thus there are more parallels between the two dimensions than one might think.
Our universe is one dimension. Heaven, where God dwells, is another dimension. Hell would be a third dimension, as it is distinct and separate from the other two. That makes three dimensions that we know of, but there still exists the possibility of more. Again, the Bible doesn't tell us everything. It's mostly focused on our reality.
Yes, I believe the book of Enoch is connected to the events of Genesis 6.
Then we agree more than we disagree.
Therefore, was Lord Jesus and those two angels in flesh bodies in order to eat the food prepared for them? I say no. Lord Jesus had not yet been born in the flesh when that Old Testament event happened. What this means is that we must... modify our understanding of what the spirit body actually is, and how it can manifest and live upon this earth, instead of believing Hollywood's fake movies about ghosts and such.
I'm sure they weren't sent specifically to eat a meal, yet scripture indicates exactly that's what they did. Even Jesus in his resurrected body was able to eat.