I got turned on to OnePlus a few years ago, they are a smaller company that makes 'flagship' quality phones but they don't sell through carriers, they are a dual sim gsm phone with all top shelf components but the best part is they run Linux over top of Android by some magic I don't really understand. Even my 2016 OnePlus 3t still gets regular upgrades and is fast and not buggy.
Plus the best part is since it's not tied to some carriers bullshit there are no bloatware or bullshit, you have full control of the phone, only the Chinese government can see and record your every movement.
The 3t I have is about on par with an iphone 6/7, the only thing lacking is not quite as good of camera as a 7, otherwise CPU, ram, all that very good. I bet you could get one under 200. Mines been in the pool and dropped a hundred times, it's a tough phone.
I'm on cricket, att network, 35$ month for 10 gig which I've never exceeded.