Ronaldo playing for Newcastle doesn't look possible to me, Newcastle might no be a 'poor' club, but the take over by the billionaires who bought the club is still relatively recent, and it is yet to have any impact on the team. It would be queer to see Ronaldo playing for a club like Newcastle, it would be a new low in his career and i don't think he will be interested in it. If Ronaldo is to stay in Europe, then it has to be a big club that's playing in the CL, if not it's better he leaves for Saudi Arabia knowing his time in the spotlight/elite football is over.
I always thought that Cristiano Ronaldo would not be allowed to play in the Champions League this season anymore because he already participated in a european club championship this year with Manchester United. I just searched that up though and i found out that he could still play Champions League for another club because he is only suspended to play Europa League this season and i doubt he wants to play there anymore anyway. I also think that he will choose a club where he can play Champions League over any offer from other clubs even if those other clubs are offering way more money. Nowadays CR7 is only playing to set new records or to improve the ones that he already reached.