ESP32 wrover vs ESP32-pico-D4/V3

[zliudr]

I'm looking at the esp32-pico-D4/V3 system on a chip solution as an alternative to the ESP32-WROVER modules. I know picos don't have SPIRAM but I can add that easily. What I've found so far is that WROVER integrates both QSPI FLASH and QSPI RAM so the bandwidth would be the highest. I'm reading pico-V3 spec sheet. It seems that a lower speed SPI (MI/MO/SCK) is used to access the 4MB internal SPI flash. So this is expected to drop performance by somewhat with both code loading/execution and file stored on flash, correct? What about pico-D4? Is that just ESP32+4MB QSPI FLASH? The flash pins are exposed so they are prone to attacks, right?

I also read a couple of designs with pico and think that only 3.3V is needed to power it and the same flash/boot logic with EN/GPIO0 is needed as for WROVER, correct? Thanks.