There are tremendous opportunities for increased sound quality. No question. But the practical problem is large. The huge effort you put into iTunes organization.
I have used iTunes, JRiver, Foobar, on PC, and MAC with direct storage, NAS, pocket drives. Then found out how much better a dedicated streamer sounds. On my streamers Streaming is better or equal to CD and stored files… if exactly the same files then they all sound the same… the same as my excellent analog leg.
But your issue is that you are trying to solve three problems with one system. If you want to continue with one solution for three problems, then it may require your low sound quality solution.
A high quality streamer (most still contain internal storage and can connect to NAS). So, theoretically you could have your master library on NAS and save and control by iTunes. Then you access it with your streamer if you want, but normally you can listen to music at home through streaming (Qobuz for sure). If you want, you can listen to your iTunes library through your streamer (minus the high;y structured organization). For DJing and other stuff you do what you are doing. This will greatly improve your home listening and you will learn all about streaming… maybe the next step would be to travel with a streamer with it’s internal storage… but that would not be the iTunes one. But that would be a later step.
Showing your audio components is important. There is no reason to pair a $22K streamer and a $22K DAC with a $3K preamp and $3K amp or visa versa. You want to match the capability of all the components as much as possible. High quality digital audio is available at $5K system level through +$500K system level.
These are just some opening thoughts. This will require some work.