The target of this project is not to win the Champions league, but to become the second, better Ajax. That means the prime target is to make profit from player sells and youth academy, not necessarily trophies. Even though you should do better than Ajax, winning the league. You could also try to find the second R9 while you are at it.

End loans:
Mvogo
Vinicius
Sadilek
Baumgartl
Luckassen

Loan out:
Ledezma
Bakayoko
Fofana
Oppegard
Seelt

Sell:
J. Drommel
P. Max
E. Gutierrez
E. Zahavi
P. Mwene
M. Van Ginkel

Budget: ~23.9 M. €
Sells: ~44.6 M. €
Budget with Sells: ~68.5 M. €

Suggestions to buy:
J. Bijlow
=> already plays in the same league, transfer weakens rival, solid goalie for a long time
=> costs: 30M. €, pay ~45 M. €
=> very pricy, but is the most realistic option, also a good goalkeeper is crucial in career mode, if you don‘t have the money, keep Droomel for a while

G. Kerk
=> nice backup, fits because he is Dutch, speedy alternative as a supersub
=> costs: 5M. €, pay ~7.5 M. €

A. Hlozek
=> amazing talent, not too unrealistic, but you might be forced to sell him at some point
=> costs: 22 M. €, pay ~35 M. €
=> sign Bijlow first, golie more important, you can keep Vinicius until you can afford him