Agreed, we shouldn't sign a player just because we can - it's what got us into this hole in the first place - going for players that are easy to sign not because they have the attributes we need in the team, case in point Zirkzee and Ten Hag's plethora of Erediviste graduates.
My view on Dorgu is that if the technical team; Wilcox, Amorim, Vivel and the scouts, are in agreement that he has the physical and technical properties to make it here then £5m shouldn't be a deal breaker. We obviously need to operate on a more efficient basis but this isn't the same as the Antony deal where we paid €100m for a €30m player.
It would be more beneficial to wait a year or two for Benfica to sell him and make a nice profit on our sell on clause than sign him, watch him fail to get to grips with the physicality of the league and then have to give him away. If Dorgu is too expensive, our scouts have to give us another option.
Not sure that he would fail, he is 186cm and whilst not built like a rugby player is hardly a weakling, as for the previously mentioned potential for making more money from his sell on clause bear in mind if he went for his release clause of £50m that is still only going to be £10m to us, unless we put him on mega wages we should easily be able to command £10m or more to sell him, so actually it makes more financial sense to buy him for £16.7m and flip him for £20m plus than it does to wait on his release clause being triggered.
I think the far more likely reason that we prefer Dorgu to Alvaro is Dorgu's versatility, he has demonstrated can play left or right, I am not convinced that even if we do sign Dorgu that we will not be back in for another WB in the summer having versatile players is extremely valuable to this system.
edit: Actually thinking about it, irrespective of anything else, it makes financial sense for us to re-sign Alvaro , it would actually be stupid not to resign him on a financial basis, (even if as a show of good will we loan him back to Benfica for the remainder of the season), it is not like we do not need cover anyway, we have zero LB/LWB as Shaw is a write off, and Malacia is not the level, obviously there are people involved , it is not FM so he would have a say in matters, but it is a no brainer to resign him if he is up for it.
If we sign for £16.7m double his current wage in 18 months if we sold for £22m we would have completely broken even and had an actual usable LWB for 18 months, £32m and we have still made the same as we would if he sold for his release clause this summer, the only down side we have had to wait 12 more months for a £10m pay out, but then we are skint, £36m in 5 years is break even £46m is the same profit, I just see zero reason why we wouldn't resign Alvaro if he is up to it, we are never going to get a better deal for a player of his quality, damn ETH for forcing his sale, and poor on management for authorising, still I guess they were going off info handed them by a man who clearly knew nothing about players given the shitshow squad he has left us with