Well, since several seasons ago, we actually all saw quite a lot of potential in Arsenal. Arsenal have basically found a good composition in their squad. It's just that what Arsenal lacks is their consistency throughout the season. And yes, in terms of second tier players, Arsenal really has to prepare the best, whose quality is not much different from the quality of the first team. This is necessary when a major player is injured.
And Arsenal really has to start making good use of the transfer market. No need to make many player transfers. But you only need 3 or 4 which are of very good quality. And currently Arsenal has made several good moves, such as Arsenal getting Kepa, Arsenal also making a verbal agreement with Martin Zubimendi, and Arsenal also negotiating to get Christian Nørgaard. And apart from that, Arsenal is also still looking for a sharp striker.
Well one thing I know is that gone are the days Arsenal relied on quantity over quality. Arsenal as at then can never bring out a huge sum of money to purchase a single player but instead will use that money and buy five to seven players. But in recent years I have seen Arsenal using £60 million and above to purchase a single player but the problem is that they have not still really got it right in majority of their big money signings. Just like you said, the management doesn't need whole lots of players like Chelsea, they just need to strength their attack and defence especially with 3 or 4 quality players.