PCSX2 supports CHD natively. You do not need to decompress them. Simply add your CHD folder to the emulator's game list.
This updated guide explains how highly compressed PS2 ROMs work, where to find them safely, and how to extract them for flawless emulation. What Are Highly Compressed PS2 ROMs? download ps2 roms highly compressed upd
Downloading PS2 ROMs is a common way to save storage space and reduce download times, especially for large games that can reach up to 4.7 GB. Most sites offer these in .7z or .zip formats, which must be extracted before use. Best Compressed Formats for PS2 ROMs PCSX2 supports CHD natively