It always needs team chemistry to win trophies, but when you have the best players in your squad the chemistry will automatically be built. But it won't be a good idea to expect Newcastle to buy everyone within the next season and win trophies already but maybe that will be the case after 3 or 4 years. Then they will have a stable squad and then they will be a bigger threat in European Football.
It is clear that the results with the tough players will be much better than with the average, but look how many times the Champions League has been won by two moneybags - City and PSG? Zero. Therefore, I would not talk about quick results. I can believe that you can create a top club for example in the French championship and seriously fight for the championship from the very first season (there is only one rival - PSG), but in the English championship, where there are always several applicants and each of them is great, this is unlikely.