When there is an irreplaceable player in your squad (e.g., Odegaard*), you don't buy a direct backup. You buy a player on either side of them (e.g., Zubimendi + Gyökeres). That way you can play a different guy in midfield (e.g., Havertz or Nwaneri) and mitigate the absence. Squad building is pod building, as I always say.**
That's why the "you can't replace Odegaard" argument is disingenuous. You can, just not necessarily with his direct backup. You have to build solutions into your squad where they are most potent. Weakness in the depth chart is also a concern, but a separate one. Sometimes you can kill two birds with one stone, but often you need to simply do both. The former is more important than the latter, and we only did the latter.
*all names are for illustrative reference only.
**I've never said this.
