The bark bumps are not quite in focus, but they look like lenticels, a normal feature of tree/shrub wood that is naturally more visible on some species than others, especially once wood reaches a certain age. Its more prominent appearance in this case is probably just a coincidence in timing, as the plant matured enough to have this feature become more noticeable. We do not see any indications of a problem. There is a native beetle whose larva bores into the base of Elderberry stems and moves down into roots (appropriately named the Elderberry Borer), and that might be the cause of stem breakage, though it's hard to determine what else may have caused it since we can't see the symptoms. Weather or wildlife might have contributed instead.

Elderberry tends to be a resilient plant that several native animals feed on, so we would rarely recommend chemical intervention even if it were effective (if this were a fungal issue, for example, a fungicide can't cure existing disease; borers are also generally out of reach of most insecticides). They should regrow easily from lost branches as long as the root system is healthy, and also tend to propagate fairly easily from stem cuttings, should the need arise to root a new plant if the original shrub is dying back.

Miri

You're welcome!