Nobody outside the top clubs can attract 'top class players'.
Both because financially they cost to much, and because they're not interested in signing for the lesser clubs in the league........
Werner is the example to both the above points.
You have to pay £15-40 million, and then hope you can progress them to becoming 'top class'.....By that point you're probably forced to sell, and the process begins again.
Take Berge.
You buy him for £20 million, you hope he adds to the first eleven for 2-3 years and progresses to the level of say Ndidi, where he is then worth
£80 million+, you sell, and re-invest it back into 2/3/4 more 'Projects'.
If you can't outspend teams, like Man City can, it's the only way to improve your squad over a period of time.
Someone like Callum Wilson, who is not 'top class' but probably at the very top end of 'realistic signing', who on average gets 10 goals a season, would cost upwards of £50 million.
So its all above developing players yourself.