If you're looking to get a 6-string new, I too would recommend the LTD B-206. I tried a preowned one in a music store and it was quite nice to play. Honestly, I found it nicer than the Ibanez Soundgear 6ers it competes with.
LTD also has the D-series 6-string, which was redesigned for 2020 (instead of having a merbau body like the previous generation of D basses, it now has a mahogany body with a poplar burl top). [Invalid or Expired Link Removed]
It's 34" scale as opposed to the B-206's 35" scale. It also has different woods and a less beveled body shape. I've never tried a D-series LTD so I can't say whether B or D is better. They both seem to be different flavors of a similar thing. Kinda like how pinot grigio and chardonnay are both white wines, but they're different flavors.
Although this review is in Dutch, he seems to really like his D-6.
Otherwise, preowned is the way to go. There are some sweet 6-strings for sale in the TalkBass classifieds. I saw a couple of Carvin 6-strings in the classifieds selling for less than half your $1500 budget. So you'd be getting a Cadillac bass at a Chevy price.