Are there sounds of mandibles clicking or cockroach hissing and stuff? carapaces moving and thousands of legs clicking together?
Try “Insectoid Hive” in the Sci-fi Player. It has lots of good elements you can break out to get the sounds you want
Also Sci-Fi Player’s Swarm Attack, and Fantasy Player’s Swamp, Hell Swarm, and Across Cursed Sands (whose Old Obsidian is a giant scorpion!).