The XR2206 VCO gave poor results. Noises on the waveforms and a reduce amplitude above 200Khz. I'ts a pitty because the amplitude modulation amplitude could have been quite handy.

I decided to go to the LZX industries cadet VCO :

https://www.lzxindustries.net/shop/product/lzxcadt9-cadet-ix-voltage-controlled-oscillator-2149?category=7

I redesign a PCB for 0805 SMD parts and I added a bit of logic with AND gate to have only one switch for the vco to be sync'ed to the vertical or the horizontal sync signal. I also added an inverted output for the triangle and square signals.

Once the VCO is ok the project will move forward quicker.

Ordering and waiting for parts is so boring....