Update: Was able to get a working solution with most messages passing by doing this:
- Reducing message rate. (Acceptable in this case)
- Trying different deconfliction timings/offsets
- Not passing any trailing 0s to the UART (Keeps packet sizes down)
- `read` vice `read_exact` as James pointed out.

Overall, I think I'm hitting limitations of this OTA setup, but am not sure. The COBS thing could help too