I wouldn't touch a phone that was running anything lower than Oreo 8.0. Pie is already out and has been on my phone for several months.
Battery life is important to me, too. Hard to use a phone with a poor battery after one with a great one. Mike suggested the Moto z3...you can get a Moto G7 Power for next to nothing.
My wife needed an upgrade from an older iPhone and she didn't want to spend more than 125 so I ended up with a Sony Xperia XA2 that just got upgraded to Pie after we bought it a couple of weeks ago. Got it for 129 on eBay.
Had been looking at this... Motorola One XT1941-3 https://www.ebay.com/i/123670768745?ul_noapp=true
Can get the above for a song...it's last year's model but is Android One so it'll get constant updates for at least two years.
I'm like you...no reason to ever spend big money on a cell phone. Those things depreciate about 5 times faster than a vehicle or more.
Nuu Mobile is still running a huge deal on the G3 and I think G3 Plus...
https://us.nuumobile.com/