I believe the SE is on the list to get updated soon, so it might be a good time to get a deal.
However, the most foolproof thing would be the buy the newest iPhone you can stomach the price of - it’ll be future proof the longest.
They won’t offer much meaningful functional difference for the use you describe, but the hardware will be viable for future updates for longer.
The 11s are cheaper but don’t go 5G.
The 12 and 13 are extremely similar. It didn’t seem like there was huge savings on the 12 over 13, but they aren’t cheaper. Storage size seems to drive price parity a lot - more deals to be had on the smaller hard drive units.