Generally with Garmin GPS devices the Edge series are for road/training with all the willy waving data sensors and the Etrex/Dakota/Oregon/Montana devices are the generic ones. There’s some crossover but as a general idea it’s not far off.
I’ve an Edge 510 for road riding – no maps, can pair with various sensors, it’s fine when I know where I’m going or don’t really care if I take a different road. I’ve also an Oregon 600 which has OSM maps loaded and I’ll use when in unknown areas or abroad and I need a bit more guidance. I can pair a HRM with the Oregon if I want to. The Oregon takes standard AA batteries so running out of juice on longer (read multi-day) rides is less of a worry.