I think there is only one way to make Newcastle perform optimally with big changes, they have to have the courage to spend large amounts of money on developments that improve the quality of playing performance.
Changing coaches, selling several players who are not so important and bringing in several players with good quality are steps that must be taken by Newcastle because all team have experienced significant improvements in performance.
If Newcastle does not keep up with developments and changes then they will definitely continue to be left behind, almost all leagues have team that have shown quite significant improvements in performance this season.
And next season maybe the competition for Newcastle will be even tougher in the English League and European League if they qualify.
IMO, if the club is serious about competing this season, Newcastle can do it. after all, they have a final that can bring in the star players they need. however, the club management did not do so. I mean, before Newcastle got serious about their project, the club still gave Eddie Howe the opportunity to do his best job. Unfortunately, he was unable to make it happen plus many players were injured. My guess is that next season Newcastle will start getting serious about competing in the Premier League. In this way, they will make major changes, including replacing a more competent coach. Thus, Newcastle is serious in competing for the Premier League trophy next season.
As you said, they will release several players and at the same time bring in a coach who can be relied on for the Newcastle squad next season. This is all done, if Newcastle is ready to compete, especially since this team is supported by PIF which has abundant finances. but this is just my personal assumption, we will find out after this season actually ends and how Newcastle faces next summer. specifically, in this summer's transfer window.