Dodge Ram 1500, v6, 6 speed manual, stuck in reverse.

If you can't shift outta reverse, something is likely broken inside the tranny. However, try shifting outta reverse while the pickup is still moving n the clutch is pressed n then try it with the clutch out n the pick up moving. These's no synchronizer for the reverse gear usually. In synchromesh trannys, all reverse is, is a gear that bypasses the main cluster of gears from the front all the way to the rear most gear.

Didn’t want to shift out of reserve

My best guess is, something is blocking the gear ass'y from moving. You can try n pull the shifter mechanism out of the tranny whilst it's still n the pick up n eyeball if something is obstructing the shifter motion. But other than that, time to split the tranny case is my only other guess.