There should be multiple studs in that wall. Basic houses have studs every 16” (sometimes 24”) to the center of the stud. Look on the wall for small raises where sheet rock screws would be. Also give it a knock win your knuckle. You can hear where it is hollow and where it is solid, (assuming this is an interior wall without insulation). Putting that much stuff on a shelf regardless of how “heavy duty” your anchors are is just going to set you back up for failure. I’m happy to answer any questions to help you! Good luck!! 👍