Any advice on a quality Lightning to 3.5mm adapter? The official Apple one is so flimsy that one or both channels cut out anytime I move the phone. My workaround is to heatshrink the cable and both ends, so it’s rigid enough not to cut out. But it’s ugly and probably won’t last more than a few months.
Use a cotton swab with some of the material plucked off to make it thinner and soak it in CAIG DeoxIT or MG Chemicals Electrosolve (you can typically buy these from Fry's / MicroCenter / online). These chemicals are made to actually clean and de-oxidize contacts.
You have dust/lint inside the bottom of the port that is preventing your connector from going in all the way. Get a fine tool and reach in and grab out the crud at the bottom. I had the same problem until I did this.