Considering My First Cycling Computer, Looking for Suggestions for a Good Stand Alone Unit

Hoping some of you can recommend your favorite cycling computer that doesn't need to be paired to a cellphone / computer to be fully functional. I've been using my smartphone up until now, but I want to be able to unplug from the outside world on upcoming trips (still going to carry a cheap flip phone in case of emergencies). I've never used a dedicated cycling computer before so I'm a bit lost. Im looking for a rugged unit that can handle on the fly route planning without any need for a separate app running on another device. I'll be using a dynamo hub so massive battery life isn't that important. Powerful stand alone navigation functionality is definitely what I'm most interested in. I'd like to be able to easily reroute on a whim to any cool sounding places I may hear about. And on a more practical note, find nearby places to restock on food and water as the need arises.