My weirdest idea for this kind of transfer is to have it transmitted through high-frequency soundwave, and there would be a PSK modulator on the sending side and a matching demodulator on the receiving side. Making one would probably be a project too complex to manage, especially since I don’t know how you would demodulate PSK in the first place

Then I realized JAB Codes exists so I use that now (though it would be better if I didn’t have to open a browser to make one)