These are not the only possibilities. A musically-based understanding of the fretboard would let you play directly from sheet music, chord charts or lead sheets. (Classical guitarists do this as a matter of course.)
Of course ear training (what you do when playing by ear) is a big foundation for that skill, but that should not be time consuming, either. A good player should be able to "find" the right note on the fretboard on the spot, not just by trial and error.
> some of the terms you mentioned are new to me
Is solfège new to you also? You know, the old Do-Re-Mi etc. That's something that even most "self-taught" people learn to sing to from childhood, and properly used it can be a great foundation for thoroughly understanding a relative instrument like the guitar.