From the playlist right click/long press a track so it is highlighted, click where it says ‘1 selected’ at the left corner of top banner that now appears, click ‘Select all’ from the drop down.
Now click the ‘three dots in a circle’ icon to the right of the ‘Play now’ button, from the dropdown, click ‘Add to Library’,
I’m not aware that you can add the whole album of each track of a playlist, other than manually.
Please, let me know if we can help with anything, @A_Joseph_Williams. We’d love to. And we’d love to do so much faster than now - I am sorry for the delay in getting back to you