Maybe I'm just new, but I just realized you can Ctrl-select or Ctrl-dblclick individual, separate pieces of text and copy them to the clipboard in one operation.
I have no idea how long this has been a thing, and maybe every clipboard works that way, not just Plasma, and I never realized it. It also lets you do things like Rt-click on it and do the regular operations like Search in Firefox. Spaces aren't preserved unless you specifically select them but search engines seem to be able...