Arduino real time video output, using potentiometers to change image.

Hello! I’m asking for some ideas on how to approach this project I’m starting, its my first and started using C++ a week ago so I know I have some more to learn, but need a general direction or input that I could use at a later date. I am currently using an Arduino Uno but will likely upgrade this to a Due in the near future for more Analogue inputs.

I want to have a program that outputs in real time black and white lines onto a CRT TV through RCA, I know that I can use the TVout library and have already started producing a couple of things on the screen (although I’m unsure of if this is the best way to go yet). The lines produced in real time need to be adjusted in frequency and width as you move up or down a ribbon potentiometer.

The reason I am unsure of TVout is that the lines spacing and dimensions are pixel based, on only a 128 x 96 resolution. My application of this software is that by picking up the static on the CRT musical notes can be played, using ‘Number of stripes x 60Hz = Output Hz’. Using 440Hz as A for example dividing this by 60 creates 7.33333333, would the TVout draw lines function be able to create accurate amounts of lines to the tv like this or be stuck at pixel increments?
Also I want to be able to play more than one note at once, I’m still a little fuzzy on how this works but I know it can be done from playing audio through the TV’s video input, it seems that almost super imposing the two line densities creates that effect.

Is what I am creating achievable and where should I begin, I’m a musician by trade so only have knowledge on the sound engineering side of things hoping you guys can share some knowledge!

40 years ago a group of students made a simple board to be used together with a commercial TV, jacking in at a proper point. I don't remember the clock frequency being used.
You likely need a quite fast controller to manage to get enough resolution to tune the output signal timing.
This task calls for good electronical and digital understanding.
It's probably easier to drop that old CRT and use a modern digital display that will be operated by more common software.