Reading more than 4 i2s channels at once?

[beastlyx]

I have https://www.seeedstudio.com/Sipeed-6-1- ... -2875.html, and am trying to beamform with the esp32s3. Alas, you really need to read all the 7 microphones at once, and there are only 2 i2s ports on an esp32s3. IE: You can read at most, 4 microphones simultaneously.
I'd prefer not to have to use some kind of multiplexing.
So, I wonder if it's possible to use an i2s port to generate the CLOCK and WS lines correctly, and read back data in SPI octal mode.
IE: Loop back the i2s clock to the SPI input clock, hook the 4 data lines plus word select (so I don't lose my place with the left or right channel) and read data that way?
IE:
[MISO0 = i2s in line 0] [miso1 = i2s in line 1][miso2 = i2s line 2][miso3 = i2s line 3][word select][unused][unused][unused]
Then, each byte I read contains my critical 4 bits of data, plus the fifth bit being word select. Each 32 bytes read, I have 4 channels of 16 bits for the left i2s channel, and 16 bits for the right i2s channel.
It's a wee bit bit bit-bangy, but I can sort the incoming bytes into their proper channels at my leisure; in bursts if need be.
Question is: how do I set up and run the SPI interface in octal mode, (and how do I set up which pins are which?) and just (somehow) leave it to read data, like all the time? (I'm an SPI newb)

[ESP_Sprite]

Would probably be easier to see if you can get hardware that can do TDM, iirc that allows you to put up to 32 units on one I2S line.

[beastlyx]

Not a bad idea. It's not an esp32 solution, though, AFAIK. (thanks)
So anyone have any ideas how to use Quad SPI mode? Esp in Arduino?