If truly Newcastle are interested in Ronaldo it will be an offer Ronaldo will accept quickly. Because right now it is not easy for him to see a club that is interested in him. Ronaldo will will prefer to be in Newcastle than Saudi Arabia. Newcastle is not a poor club, am sure Ronaldo would love it.
Newcastle isn't a club which enter Champions league and Ronaldo isn't a player who played in Champions league too, so what's the relation with this thread? you're discuss about football transfers.
I think 38 is not a negative for Cristiano. We watched Zlatan again with his good performance at this age. Ronaldo can show this performance in the same way. It just takes a team that believes in it. He was 37 years old last year and had done well for Manchester United. Cristiano Ronaldo probably plans to play football until the age of 40. Later, he can step into his coaching career.
Zlatan Ibrahimovic's performance already decrease and he's currently injured, he's expected to comeback after next 3 months. The reason why I say this is, he join LA Galaxy and AC Milan are free transfer, which mean the previous clubs doesn't interested with him anymore.
Also Ronaldo ever said he's not interested in coaching career, he can make huge money without need to work in football career, many brands will still ask him to promote their products.