My zenfone 8 is solid, but has high treble when listening on max on my headphone and Planar IEM. I would not necesserily recommend builtin jacks. If you can choose a lot cheaper device for lack of a jack, you can get a fucking great bluetooth adapter and a very good IEM from the difference.
Apart from that, I recommend Gigaset/Volla and Fairphone since they are servicable and have removable batteries.