Roots are waterlogged. Can this tree be salvaged

Yes, the root ball actually doesn't look too bad. Buy some bonsai soil, repot it into something a little larger than the root ball, and water it as needed. I favor a slender wooden skewer inserted into the soil for several minutes to monitor the need for watering. When the skewer comes out slightly moist, time to water. If quite damp and holding onto little bits of soil, no watering needed. Other than that, lots of sun and weather to help it grow.

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Make sure that when watering, the water runs out the drain hole almost as fast as you pour it on, to ensure adequate drainage. For mine I use 100% turface (calcined clay) with no actual soil (dirt).