I'll +1 to most of what has been said.
I played fretless exclusively for 5-6 years. In the learning phase, I too noticed you had to be very close to where the fret should be (proper intonation, standard tuning, etc). When I transitioned back to a fretted bass, I found my technique was better than before. Previously, on a fretted bass, my fingers would land randomly between the frets. I made music, so I thought I was fine. After the fretless work, I now know my technique is much better and my notes are cleaner regardless of which type of fingerboard I am using.
Good Luck OP
I played fretless exclusively for 5-6 years. In the learning phase, I too noticed you had to be very close to where the fret should be (proper intonation, standard tuning, etc). When I transitioned back to a fretted bass, I found my technique was better than before. Previously, on a fretted bass, my fingers would land randomly between the frets. I made music, so I thought I was fine. After the fretless work, I now know my technique is much better and my notes are cleaner regardless of which type of fingerboard I am using.
Good Luck OP