They've been engaged with plenty of times. I'm fairly sure I spoke about them with you in this thread.
If the level of control people believe he has is what the club granted, then he should never have been hired, which effectively pins it back on the club. After that, you can criticise him for demanding the control and his record with that control, but it still has to be caveated with "why the feck did the club give it to him?".
It's a short quote, that literally begins with "I don't want to be sole-ruler, I stand for cooperation" but people focus on the "control of transfers bit". It can just as easily be read as him not wanting surprise signings, or players he categorically doesn't want forced on him. You literally described this situation to me with Emery and Pepe at Arsenal, prompting a change in approach for Arteta.
He has a veto, as does Murtough (Solskjaer also alluded to a scout having one, and I imagine the person authorising the financial aspect also has one). Any level of control he has outside of that is basically conjecture from both sides. Using Antony as the example (as everyone does), there's basically a sliding scale of "the club had no alternatives, so we went with a player Ten Hag knew" to "Ten Hag really pushed for his own player". Ultimately, we don't know who was the driving force behind this, or any transfer we've made since Ten Hag joined, but there have been (worrying) reports from inside the club, particularly from when Ten Hag arrived, about how ill-prepared the recruitment side of things were. Even the "500 right-backs" comment made about Wan-Bissaka paints a picture of a recruitment team not really knowing what to do with the data at their disposal, and this was publicised by the club as a good thing.