Use a full body harness ... Hunter Safety System (HSS) is the harness I use. I had the original version reversible (orange/cammo) and it worked fine. It can get into the 90F's here during bow season, and this one was pretty hot on those days so I bought the mesh version. These HSS harnesses are relatively expensive but they are simple to put on, stay out of the way, are strong with a fall braking stitch-tear design and are quiet. The "vest" version gives you some additional space for small stuff.

Several friends use the "Seat of the Pants" system and they like it as well.

Every ladder and climbing stand maker that I know of includes a simplistic full restraint harness. These work fine but most are not user friendly.

Whatever you do, don't settle for a waist only restraint. I could argue that it is better than nothing, but in my opinion, barely. You cut-out wearing one of these and need it to support you for any length of time and you'll be very lucky to avoid asphyxiation. .