Outside of PWA support i dint think so? That said, I've uploaded before from my phone thru chrome and it was just fine. Some of the sites are also mobile optimized. I used RSSBlue in the past but they're merging services with fountain soon so it doesnt make sense to jump in there until after. There's other options though I'm less familiar with the various options.

You don’t want to use wav. Most podcasts are mp3, so I recommend mp3 files.

That's another thing id love to see change if possible (i dont know what are the barriers). Mp3s are compressed... not good for music.