User it from source, if you can. I've used bs4 via npm, I copy variables and, mixins add a copy of the bootstrap.scss editing that to points to the npm directory for the rest. From there i comment out most of it, only using the starting bits. Uncommenting as I need it. I can reference the copy of vars and mixins as needed in my components' scss.
It's much more useful from source this way. Changing variables instead of monkey patching. I also have become less reliant on the plugins scripts, using the bits i need, as needed.