Safari I believe doesn't support mp3 natively, and there are some libs on github that solve this. When I was implementing mp3 playback in my podcast project, I had to save two versions of the mp3: .mp3 and .m3u8 (for safari), which is a pain, apple isn't making simple things easy.
#.mp3 hosted on R2 can't be played back only on Safari (Mobile/Desktop)
edgy ice
rustic storm
fixed. issue was unrelated with cloudflare.