

I use fre:ac. It is open source but I’m not savvy enough to see what the license is.
I don’t use MP3, I use AAC. Never liked Opus. I get it’s a free/open codec, but I’ve never liked the format. So I’m not sure what the licensing is for AAC. But I’m sure fre:ac can do Opus as well.
Firefox. My daily driver is an iPhone and I just use Safari there, but we have uBlock Origin Lite now. But on Android it’s Firefox with full fat uBlock Origin. As it happens, I’m on the Android device now! I love its keyboard so much. Apple couldn’t make a keyboard to save their arse if it came to it.