ESP32-S3 options to transfer parallel data with external clock?

[Demirug]

For an upcoming project I am looking into options to send data from the ESP to an external device. The catch is that the clock (~1.5MHz) is generate external, too. As the reference manual is not completed yet I was checking the datasheet.

I might have missed something but the only peripheral that can send data with an external clock are the SPI2 and SPI3 in salve mode? And both support up to 4 data lines in salve mode? The 8 line mode on SPI2 works only in master mode?

As I would need 12 bits (optional splittable in 8 and 4 bit) my only option would be doing it somehow directly with the GPIO?