If Newcastle wants to be able to compete in the UCL league, they have to bring in several star players. With a squad like now it's difficult to compete. They will take part in a lot of competition next season. Hopefully British representatives like Newcastle can give a decent fight next season.
Obviously, if Newcastle wants to compete in the Premier League as well as the champions league, they would need to bring in several players and not necessarily star players. They would just need capable players that are able to replace the first team players whenever needed.
I’m pretty sure Newcastle would be thrilled to play in the very competitive champions league and I bet they would go all out to make the proper adjustments to the squad. I believe they know they would be up against other top clubs from other leagues and hopefully would be prepared for it.