Flutter Form Validator Vs TextEditingControllers

Hello guys!
Today we will be learning about the differences between flutter's form validator function and the TextEditingController feature for your form inputs authentication.
I will explain with my story.
After almost completing my To-do app which I plan to publish but probably never will, I decided to work more on user auth because the tutorial video I was following did not really focus on that part. So I had this crazy idea to do Fingerprint auth, and Google sign in (story for another day) but I knew I could not do any of these without strengthening the form inputs authentication process, so I set out to do so.
After asking google how to do this, I chose the GeeksForGeeks article on Form validation in Flutter because it's one of my favorite sites.
I was immediately impressed with the simple, straightforward way of the validator function, and remembered I had actually done something like this on another app I was working for, but that time, I was working with some high level engineers so I just copied code, obviously!
But this time, with my very simple To-do app, I liked the simplicity of the validator function and immediately implemented it in my code. I felt so proud!!

But then, I knew somehow the Text Controllers had a part to play so I was curious why the validator function did not even use them.
After more digging and research, I realised they are both used for user input validation, but TextEditingControllers are recommended for smaller size applications like my beloved To-do app because for a larger app, with numerous controllers, it would be a problem managing all the controllers efficiently.
With Google's recommendation, I dived in to using TextEditingControllers in my code instead of the validator function. Andrea helped with this one from her blog Flutter text field form validation
I was excited to implement the feature where you're prompted in real time if your input is correct or wrongly formatted, and made me feel i'm building a high class app.
But when I got to the part Andrea said

"It's bad UX to display an error message even before your user starts typing"

I suddenly lost all excitement.
And when things like ValueNotifiers were coming into the picture to solve that, I changed my mind on using TextEditingControllers for my form input authentication.
Call me petty, but I still got the job done.
After going back to my beloved validator function, I realised it was going to be a hard one using validator on extracted widgets, I did not even want to think about using outside (user defined) functions for validation at this point, and so I just un-extracted every textformfield widget.

Thank you for reading this far, it was fun writing this.
Till my next one.
Peace!