Not sure if you found a source.
I have been able to find one supplier: https://www.solder.party/docs/flexypin/
If you find any more, please post here.

Thanks for that link, it lead me down a few paths to test.

Arduino version 1.0.6 library works correctly
Arduino version 2.0.0 library works but is slow
Arduino version 2.0.2 library fails badly as we know

https://github.com/espressif/arduino-esp32/issues/6081
leads to
https://github.com ...

Check https://github.com/espressif/esp-idf/tr ... esp32-only.

For reference : https://github.com/espressif/arduino-esp32/issues/6164

Hope this helps

I have also been having issues with SD speed and have been troubleshooting.
I found a benchmarking sketch that helped me. (https://www.instructables.com/Select-SD-Interface-for-ESP32/)

I modified it heavily to test with an ESP-Cam board. (MISO:2 MOSI:15 SCK:14 CS:13) and runs in 1bit/4bit/SPI ...

I have just found this post as I was looking for the same details.

If you have not yet found the answer the below is working for me for setting channels with ESP-Now only use.

WiFi.mode( WIFI_STA );
WiFi.disconnect();
int chan=11;
ESP_ERROR_CHECK(esp_wifi_set_channel(chan,WIFI_SECOND_CHAN_NONE ...