1Ch 28:5 And of all my sons, (for the LORD hath given me many sons,) he hath chosen Solomon my son to sit upon the throne of the kingdom of the LORD over Israel.
1Ch 28:6 And he said unto me, Solomon thy son, he shall build my house and my courts: for I have chosen him to be my son, and I will be his father.
1Ch 28:7 Moreover I will establish his kingdom for ever, if he be constant to do my commandments and my judgments, as at this day.
I have pointed out something that you really should know already, but just in case, I'll repeat it.
Many prophecies have 2 fulfilments: a proximal one, and a distal one: meaning one near, and another further along IN TIME.
That is the case here. Solomon was the first, lesser fulfilment, and Jesus the second and far greater one.
The proof of that is in 2 parts:
1 Solomon was David's son. Jesus was God's Son.
2 The kingdom was to last forever. Solomon's didn't. Jesus' will.
Therefore you're back to square one.
Was Jesus God's Son at the time 2 Sam 7 was written? I'm certain you know the answer to that is 'DEFINITELY NOT'.