What's your question? Ask

While most Elderberry plants are susceptible to various fungi, viruses and borers, Black Lace is particularly susceptible to Verticilium Wilt and borers. The only way to confirm if a disease is causing this dieback would be to send a sample to a diagnostic lab which you may want to do if the same pattern occurs in the next growing season.

For now, I suggest you prune back your plant to within a foot of the ground (which will encourage new growth in the spring). As you cut off the woody stems, look to see if there is any sign of borer damage on the inside of each branch. If not, then most likely the dieback was caused by a fungus or disease. Except for Verticilim Wilt, most diseases are manageable with the use of fungicides and good environmental controls.

The root system is shallow, but take a wide area around it.
Large trees, up to 70 feet or more should be planted at least 20 feet from the home, medium-sized trees up to 70 feet tall, 15 feet from the home, and small trees 30 feet tall or less, 8 to 10 feet from the home.

That would be Sambucus nigra, or the Elderberry.This article will help:

https://www.gardeningknowhow.com/edible/fruits/elderberry/elderberry-bush-varieties.htm

Transplanting in summer adds heat stress to the already stressed plant. You need to keep it well watered (but not swampy) to help it recover. Hopefully you got most of the roots in the translocation. Mulch around it to conserve moisture and keep roots cool. If it is in a full sun site consider erecting a shade cloth for the hottest part of the day.

https://www.gardeningknowhow.com/plant-problems/environmental/dealing-with-heat-stress.htm

https://www.gardeningknowhow.com/garden-how-to/info/shade-cover-tips.htm

The stripped bark could be cankers. Here is info about those.
https://www.gardeningknowhow.com/ornamental/trees/tgen/cankers-on-trees.htm

I would remove the suckers. Pruning can stimulate the production of suckers.