Hey there, as I said above I ended up making a custom node in C++ to convert a wav file. Instead of saving the actual USoundWave I save wav files and save the filenames as strings. Then every game session it goes through the list of wav files and converts them to USounds.
This worked well for me because I also need to import wav files so I can just use the same system for both, there could potentially be a way to save a new USoundWave directly with C++ but I didn’t look into it.
If you like I can share the code for the conversion blueprint I made, but as I said it will still not allow you to save a USoundWave permanently.