Take a look at the new one plus phone that is about to be released. It is heavily.implied that it will have a headphone jack. Should be sub 600$ and if my OP3T

Take a look at the new one plus phone that is about to be released. It is heavily.implied that it will have a headphone jack. Should be sub 600$ and if my OP3T is any indication the software experience and lasting ability of their devices certainly up there with any other major manufacturer. Cons: Chinese company, so you never know who is looking at your data. They do let you root and unlock bootloaders, though. So there is that. You need to install the Google pixel camera app to get camera performance that matches other flagships. Thankfully my 3T got the app ported without root and I would expect the same for the new upcoming phone.