>If i understand correctly we need to flash a first time via UART and activate USB CDC as such.

Yes.

ESP32-S2/S3 can use USB CDC.

To use this function, you need to write firmware that enables this function.

Writing firmware that enables USB-CDC and resetting will enable USB-CDC, and from then ...

Hello, I am using an esp32 s3 FH4R2 in my PCB. I want to be able to flash via USB. I am able to flash via uart and and uart to usb adapter however i can't make USB be detected.

Things i have tried :
Checking power lines
Connecting a VBUS to a GPIO
Installing tiny USB and configurating it in menu ...