You say we have options but you literally don't know what those options are.
There's no serious indication that Madrid will sell Guler. Xavi Simons apparently isn't allowed to leave for less than his release clause (~£70m), which makes sense because they basically paid that for him. Mbuemo is not going for ~£30-40m, he has one year left, plus the club has an option for a further year so he has two years left on his deal (if Mbeumo was available for £30m, I think the whole league would be after him). Cherki's ~£25m verbal (!) release clause was only valid during January to the best of our knowledge.
It's great to say why are we doing this, there's better options here? But if we are going to have a go at what the club are doing, let's be serious and not make up what the options are, it serves no purpose.
What we do know, is that the club value Cunha, and appear to be willing to pay his release clause. Cunha appears to really want to come here and we aren't a second or third choice or whatever. We could look at this and say, he's performed very well in the PL, he's got a release clause that in line with his contributions for his time in the PL is actually reasonable (subjectively, I get that) and with him reaching what should be his prime years in his career. So we could be excited about this deal and what we know it entails. Or we can choose to pretend that there are all these other options on the table, despite not having a clue if they actually are options?