Actually, with the current performance of Newcastle, in my opinion, Eddie Howe should feel threatened because in fact they are currently experiencing problems and crises in performance.
Newcastle have spent quite a lot to make their readiness in a good position and are considered one of the dangerous clubs in the last 2 seasons so it is certain that when the conditions are not in accordance with the desired expectations, the coach must be ready to bear all the decisions because it is certainly the coach who will be targeted because he is considered unable to advance the club.
Howe can get out of this trap if he is able to improve Newcstle's performance but if in the end he cannot do that then he must be prepared to leave.
You are right about almost everything but one thing is wrong. You said that Newcastle United spent a lot to get the team ready for the fierce competition in the Premier League, but that is not right and it is something I criticize. Newcastle would have had the money if they wanted to, but they spent only £130.8m and their net spending was £88.6m.

They are pretty much in the middle when it comes to their spending and I think when a club qualfies for the Champions League and has played such a great season, they should make sure that the squad is competitive the next season. That's where they saved too much money in my opinion.
I don't know the data you provided in the picture is from one season (summer transfer this season) only or talking about the last 2 seasons since Newcastle tried to revolutionize their club for the better.
But for the spending issue I said in my previous post I said that they spent quite a lot of money in the last 2 seasons meaning not just this season alone.
We can see some of their purchases in the last 2 seasons to make the club better such as the purchase of some players who spent more money including when they brought Harvey Barnes for 44 million, Tonali for 64 million or even Isak who was bought for more than 70 million.
Even if this price is not as big as the spending of some big clubs like Chelsea, Arsenal or maybe some other big clubs in the EPL but it is big enough for Newcastle to overhaul their players to try to do their best to make them one of the strong clubs after the acquisition of investors from the middle east.