In a recent interview with Auto Motor und Sport, Newey has now revealed his reasons for making the switch in further depth.
"I think that goes back slightly, I think if you’d have said to me 12 months ago, would I be leaving Red Bull and then now ultimately starting again, I would’ve said, ‘no, you’re crazy'," he said.
"But for various reasons, I felt I wouldn’t be true to myself if I stayed at Red Bull so, the first difficult decision was exactly that, do I stay or not at Red Bull, so I obviously came to the conclusion that if I’m being honest with myself I couldn’t."
Newey’s departure from Red Bull undoubtedly impacted Red Bull last season after the team had to contend with their decline in performance in a torrid year both on and off track.
"I think you underestimated how hard the year was for Christian," Steiner said.
"I think he will remember the '24 years as [the] pretty s***tiest year of his life, you know, with all the stuff which happened, and so we have to give to him credit.
"He always stood up for it. You know, we don’t even talk about the beginning of the year, his private stuff, but then going into it, it’s pretty clear, they had that one driver in the team.
"They couldn’t defend the constructors’ world championship, because they had only one car.
"Obviously, they lost some people. They lost Adrian [Newey], they lost Jonathan [Wheatley], they’re going to lose the strategy engineer Will Courtenay, which are all very good people.
"As much as Red Bull has got a good second line, these people are there a long time. They know the ins and outs, and sometimes having new blood in is good, but you need something – replacing an Adrian, it will be difficult.
"But only time will tell what Christian can make out of it, but I think it is not getting any easier for him in the moment."