Should I just accept it or leave?

The thing is, eight months ago I told my supervisor in a meeting that I would like to change departments and go to another department internally. He assured me he would look into it and that it was doable. Of course, not much happened; I kept asking and probably created a bit of pressure by doing so. The only thing that happened was that he went to the relevant department and informed them. Unfortunately, there was never a real plan as to how and when I could move. To be honest, I felt a bit strung along. Of course I understand that you can't move overnight; three months would have been acceptable, but now it's been eight months. The move is imminent, but one thing still bothers me: there is no real plan. I communicated from the start that I would not be continuing with my old projects and could take on new ones. That's simply not possible in a normal working day. I don't know, I'm somehow thinking about looking for something completely new. Even the change feels strange now. I'm almost starting to suspect that 8 months was just too long and that it took too long. I'm undecided. I like the new team and I think things could be different, but the prospect of being stuck in my old department for even longer makes it difficult, and sometimes I really don't feel like going to work in the mornings. It might also be the project manager; many people struggle with his organizational style but just get over it. But it's really annoying, and regardless of whether I change departments, I'll still run into this person in the future.

I'm not sure right now whether it's time to draw a line under it and leave or just wait and see. I just don't want to lose all the fun in my job because I've played along for too long. On top of that, a lot of colleagues have quit in the last year and I know the reasons, and these are also things that I've noticed negatively and that bother me. So I'm not that far off the mark with my assessment of what's going wrong. I just have the feeling that people don't really understand my motives for wanting to change jobs. If I say I'd like to do road planning and then I'm sent to a drainage course for railways and the comment is almost the same, I don't really feel understood because it's definitely not the same for me.

How would you handle such a situation? I know it's ultimately my decision, but I would appreciate it if someone neutral could evaluate the situation and offer advice. Also, whether it's too much of an exaggeration and whether it's normal in the workplace for there to be organizational problems in the office.