Still think it's mad that the person who has to pick the team, tactics and coach the players doesn't get the final say on who those players might be. Instead someone detached day to day from that is.
Of course a manager can screw up signings. If they screw up too many they should get the sack, and poor signings leading to poor results would probably see to that. But a director of football and scouting team could screw up signings too. And IMO are more likely to compared to a manager and his coaching staff. If a manager is old-fashioned and doesn't want to use the data and analytic tools at the club's disposal, then fire them (or don't hire them in the first place), but if they're getting on board with that and listen to what the scouts/data says, why shouldn't they then get to choose which players out of that the club sign.
DoF can get involved with the business details of transfer and player contracts (pretty much doing what a CEO/COO would do at a smaller club) and can run any specific players requested by the manager through the scouting team and choose whether to pursue it, but a manager should ALWAYS have veto on any signings suggested by the scouting team/DoF.