I'm currently building a RP2350 board with the HDMI/USB and I2S Audio I have also added the 16MB SRAM and higher vCore for overclocking which the RP2350 supports for a similar personal project to this. My first PCB had a few newbie mistakes which due to my lousy hand/eye coordination I wasnt able to fix so I am spinning up a V2 to go to JLPCB in the next week or two (https://rodyne.com/?p=3999). Your post resonated with a lot of why I am doing it so keep up the good work.