I'm using, believe or not, a Samsung Galaxy S (now called S1) for calls and texts. I also use some of the stock apps, like music player, calculator, calender. But no internet as the browsers won't load current websites. The battery lasts a few days before needing recharging.
For internet and as a mini computer, I've got a Moto E3 (2016), bought secondhand for about £30. Works well enough for me, the only thing is it takes a few seconds to dispays maps on Osmand maps.
Both of course have replaceable batteries and SD card slots, and headphone sockets.
For a phone that you're going to keep for a long time without spending lot of money, I would say go for a 2-3 year old phone with expandable memory and a removable battery.
I spent quite a lot of time looking for that type of phone and found only Moto phones had those features, and even then some Moto phones had fixed batteries and memory.