If you are determined to keep your game running on the native v2.00 file structure without downgrading, you must manually bypass the archive blocks as documented on the GTAMods Wiki .

Re-routing game files specifically to let custom assets bypass the v2.00 restrictions. 🚀 How to Mod GTA: San Andreas v2.00 Method 1: The Downgrade (Highly Recommended)

Search for the popular community-made "GTA SA Downgrader" or automated steam-to-v1 patches.

Run the executable and point it directly to your Grand Theft Auto San Andreas folder.

Are you looking to install a (like custom graphics or map expansions) or simply trying to get a clean base game running with controller support? San Andreas v2.0 Modding - GTAMods Wiki