I don't think OP 5T's camera is inferior to S6. It will be inferior to S7 as S8 didn't make a big upgrade over S7's sensor (just improved low light photography a bit). OP 5T lacks OIS though, maybe that's why S6 beats it in some pics but overall I won't say 5T has an inferior camera if you can take shake free photos.
Just get LG G6, change its launcher, apply themes to change its default icons & all. I'd suggest Nova Launcher Prime or Google launcher. It's an android device, not Apple.
Four settings to change on the LG G6
Due to the theme engines I personally prefer skinned UI over stock as there's no need to root. Rooting decreases the reliability of your phone. Even the stable ROMs give some issues or other in long run. I have used my old Nexus 4 with just custom ROMs for 2 years & I used to change ROMs every few months. I used my Z3C with custom ROMs for a year & it was running stock for over a year, I can easily say custom ROMs aren't reliable.