I can't find the words for my problems. But this is the ply I want to repair.
Due to its composition, i.e. multiple thin sheets of differing wood species glued together at alternating right angles, plywood that is damaged or weathered presents difficulties to repair. Nearly any effect might be achieved using a sufficient amount of epoxy, time, money and effort but each project has it's natural limits as far as what you are willing and able to invest.
Simply sanding down the roughest bits and painting it might be the simplest and easiest option. If it is going to be an indoor shelf or rack, depending on the use it is going to see, paint should hold up just fine so long as you can remove the loose and delaminated bits.
It may be viable to cut away the worst of the frayed edge and fasten a new piece of material to the edge using fasteners and/or glue. This is often done in furniture and cabinet making in order to hide the exposed edges of plywood. Of course, it is usually done on new material. However, depending on the state of the material within it might be workable. You may likely wish to sand and paint the finished piece in this scenario as well.
Another option is to leave it as is and go with a raw, modern industrial aesthetic. This option might sound entirely flippant (to be fair it is partially meant in jest) but depending on the origin and life of the material, the evident hard usage might be valued for the story it tells. For instance, I have seen craftsman use old workbench tops to create new projects leaving the surface scars of work and time intact. Often a clear coat of urethane is applied to protect, emphasize and in a way freeze the surface just as it is.
As with any repair, it is necessary to weigh the benefits and cost versus replacement.