To work with external harddrives you first have to “import” this drive into Lightroom Classic. After that, you can move folders from one drive to another and Lightroom Classic will keep track on where the images are stored. If you move folders outside of Lightroom Classic, you have to relink them every time. So I definitely recommend organizing your folders directly within Lightrooms folder-panel.
What hard drives are you using – SSDs, NAS-drives, old spinning drives? Let me know in the comments below!