Spirea nipponica ‘Snowmound’

When I arrived this shrub had been pruned into a very dull ball. When I cut it to the ground I discovered the plant label, and realised that it has an AGM.

In 2017 it was superb and flowered well. It seemed to suffer from the Beast from the East in 2018, and the subsequent drought. Most of it died, and a bracket fungus seemed to indicate the end.

Then, earlier in 2019, part of it made a miraculous recovery. What next?