declare SCRIPT_PATH
# shellcheck disable=SC2034
SCRIPT_PATH="${SCRIPT_PATH:-$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)}"
can be simplified to
: “${SCRIPT_PATH:=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)}"
per http://mywiki.wooledge.org/BashSheet#Parameter_Operations