sbomgr is a simple utility that can install packages (and resolve their dependencies recursively) from slackbuilds.org. ! Please note that you should check out README of package, if something goes wrong.
/usr/sbin/sbomgr [link]
[link] - https://slackbuilds.org/repository/[version]/[category]/[pkg]/
i.e. https://slackbuilds.org/repository/15.0/development/notepadqq/
git clone https://github.com/thm-unix/sbomgr
cd sbomgr
pip3 install -r requirements.txt
cp sbomgr.py /usr/sbin/sbomgr