I don't know what your budget is (and this will be a bit "spendy" for a first instrument, though it's the path I took)
https://www.acousticguitarforum.com/...d.php?t=525502
Check out the 5-course mandocellos (essentially a mandocello and an octave mandolin combined) by Dammann in my thread above.
Note that they also make them in a guitar-shape (see the Dream Guitars link in the second post on that thread).
You can get the pairs of strings as either unison or octaves.