Is there a better pattern than "log after, not during" for USB-only debugging?

I'm working with an Adafruit RP2040 Feather ThinkInk in Rust to drive some e-paper panels. The catch with this board is that there is zero hardware debug access: no SWD header, no footprints, and not even underside pads because the 24-pin FPC latch and display circuitry take up all that space. USB is my only way in or out, meaning defmt-rtt is out of the picture and I'm stuck using defmt-bbq and usbd-serial over USB CDC. The issue is that I have two constraints that absolutely hate each other: ...