Smartphones

Are there any so-called smartphones out there newer than an android 5.0 that specifically has at a minimum:
6 Gig's of RAM
USB-OTG that actually works
Removable battery
Available Unlocked
Under $200

Reasons: 3 G's RAM is pathetically inadequate for basic use much less the touted music & videos advertised, plus apps that auto-start or do not shut down when you exit taking up needed RAM for execution of instructions causing active apps to file swap increasing the heat (cause of battery fires/explosions?) & shortening the life of your phone and battery.
There's never enough memory, thus OTG for thumb drives which hold more memory, or any other android compatible devices I might want to plug in to it.
Unlocked is obvious, elimination of bloatware and swap out worthless apps like Contacts & QuickMemo+ for something more robust.
I want something that actually can do some work and built like a tank, not look pretty.