The developers of Baldur’s Gate 3 designed most questlines so that they may be completed in multiple ways. Thus, giving the players more freedom in how they approach situations. This guide represents one method that is confirmed to unlock this achievement.
A full achievement guide is available here:
https://tigorestips.com/dnd/baldurs-gate-3-achievements-trop...Locate the Spider Matriarch inside the Whispering Depths under Blighted Village in Act 1. You can reach the Whispering Depths by interacting with the well in the middle of the village. Or, you may open the large locked door near the entrance (east side). If you go through the door, you will need to destroy a broken wall near the end of the cellar.
After clearing out the first set of spiders, make your way to a room in the south and interact with the chest. Collect the Spiderstep Boots.
When you find the matriarch on the west side of the area, toggle group mode off and sneak around with a rogue that has quiet ranged attacks. Make sure to equip the Spiderstep Boots to avoid getting stuck in webs and alerting the spiders. Destroy all 3 clusters of spider eggs (2 on the upper pillars and 1 below) to unlock the achievement or trophy. You do not need to kill the Spider Matriarch, but you do need to prevent her from hatching any eggs.