Using hugo modules to substitute symlink from themes

Newcomer here:

With the introduction of modules and phasing out of symlinks from themes, I am trying to figure out how to restructure my site.

Right now I have a node_modules folder with bootstrap css in it. I symlink some css files to my themes directory. In my header partial, I reference these css files from the theme directory.

Now that theme symlinks are being phased out, what is the best way to use hugo modules, or any other tool, to support the usage of bootstrap css files in my theme folder? Not aware of the best practices. Thank you.

For reference, this issue on github is very close to the issue I am having right now: