They have plenty of money now, probably the richest owner in all of sports world as of right now, so if they want to buy a striker, they can buy anyone they want.
However, financial fair play is still a thing and they can't just spend whatever they want, no idea how Chelsea did it, that was something unreal to see, I still think that something about Chelsea will come out in day light one day and they will get punished, no way a team could spend close to 600 million in a single year without having any financial fair play trouble. All in all I am guessing that the best thing for them is to just spend the max they are allowed on big names, because that will open the doors for everyone else.
Looking at the several transfers made by Newcastle, actually from last season they have been able to sign players labeled stars but it seems a little held back, but on the other hand with the current conditions it is still pretty good.
At the moment they are still choosing to look for what is needed and it is proven that some of their transfers have good prospects but indeed it is increasingly possible that there will be some good players there because as we know they are the richest club now so they can just do whatever they want.