I have theory, and I feel like chapter 967 along with chapter 19 strongly hints at the location of Laugh Tale.
A few things first in Chapter 19. Buggy is shown eating the fake devil fruit, and one of the Roger Pirates says that devil fruits were a [rumor] to begin with, meaning at ths point, no one in Roger’s crew had a devil fruit.
Later on, Buggy eats the real devil fruit, loses his “tresure map” and dives for it, but cannot swim cause of the devil fruit.
As we see in chapter 967, the Roger Pirates charted the final island, but as they drew close to Laugh Tale, Buggy came down with a fever and he and Shanks stayed behind, so he never reached Laugh Tale. You can clearly see Buggy asking Crocus to take him with them, but he says No. I think this is clearly hinting at the fact that Buggy would literally die if he went to Laugh Tale as the journey is under water.
Next part, is about the “treasure map”. Buggy in Chapter 19, finds a treasure map, and according to him it’s the first one he’s ever seen, and the treasure lies at the seabed.
My theory is that what Buggy actually finds is the map to Laugh Tale. In chapter 967, Roger asks the crew if they found the destination to Laugh Tale after gathering the four Poneglyhs, and we see the crew with a map drawn by Scopper Gaban, and they affirm that they found it.
So my theory is that Buggy actually just found the map to Laugh Tale and that’s why Buggy can’t go to Laugh Tale as he would drown.
Laugh Tale being at the seabed also makes a connection with someone else’s theory of the D. standing for Davy Jones, and we know that Davy Jones’ Locker is at the bottom of the sea.
*Theory by WeThe6IX