I can’t receive much from my home QTH, but one thing that seems to squeeze through all the interference into my EFHW (end fed half wave) antenna, is morse code. Ill spin the dial on my Yaesu FT-897 and hear some beeping faintly in the background. Even when no other signals, not even FT8 can make it through!
I just found this project by Folkert van Heusden, that splits up a standard IP packet and then encodes the data to morse code and generates an audio file!
I can’t imagine it ever being practical, but its an interesting approach to a problem. Perhaps it could be used if a licence only allows an operator to use CW but they want to try data modes?