Well, if you’re using bluetooth to hit your stereo you can get a receiver that jacks in and sits next to it to keep the phone dongle-free. There’s real cheap ones and some higher end ones with better DACs in them (if your stereo doesn’t have a DAC). But it’s not much more difficult to set up a DLNA Media Server or get a chromecast receiver to stream to your stereo over wifi without needing to compress the audio the way bluetooth does.

I’ve also got a bluetooth DAC/Amp with a 3.5mm and 4.4mm jack that you can clip onto your clothes. Basically putting the dongle on the end of the headphone cord instead of the phone. But it runs on a charge. You can use any sort of wired headphones that you want (or connect to a stereo) and not have to be physically connected to your phone though.