Not relevant for OP.
Proper ETS is always relevant.
But on the other hand indeed, OP has do really decide his BW requirements. If Digilent's 30MHz analog and 100MS/s (50MHz?) digital are enough then it has some killer features for the price: 2CH 14bit in, 2CH 14bit out, 16ch analyzer and
16-channel pattern generator (3.3V CMOS, 100MS/s) that suddenly got me all sweaty and wanting to buy the damn thing (so far I've used Arduinos for patterns).
Much more complex choice with Pico because they do not have >8bit MSO (do have >8bit 4ch). However reading the FFT thread - 8bit Pico seems to operate pretty much at theoretical limit so 2206B MSO at 559€ might do the trick (50MHz, 1GS/s, 32MS memory, 16ch digital 100 MHz (200 Mb/s) and
>52dB SDFR @ 100kHz) ...depending on what OP means by
audio. For example my good friend means gold vinyl needles made in Japan couple K€ a pop...