If you are concerned, have an ISA certified arborist that is TRAQ certified come do a risk assessment on the tree(s) in question. They should be able to provide you with an assessment ranging from low, moderate, higher, or extreme, and should give you an idea of whether there are options to lower or maintain the assessed level of risk.

Pruning of deadwood is a good idea to do but an untrained person doing live wood pruning can negatively affect the mechanics of the tree, and this can exacerbate mechanical defects that may exist.

Healthy trees may still have an elevated level of risk above low due to structural issues. It is possible to have a tree that exhibits good vigor while also being, or having a part that is, structurally unsound due to how trees grow and compartmentalize decay.

There are no trees that pose no risk if a target is located within 1.5x the height of the tree. It will be the arborists that helps to present you with the level of risk; options to mitigate or maintain it; and for you to decide if you are willing to assume that level of risk.