If you absolutely need the full power of the official tool with none of the security risks, the best choice is a subscription to itself. Adobe offers a Photography plan for around $9.99/month, which includes the latest Photoshop and Lightroom. This gives you all the modern features, cloud storage, constant security updates, and full official support.
Avoid searching for "Adobe Photoshop CS2 Portable Google Drive." The files are outdated, highly unstable on modern computers, and frequently infected with dangerous malware.
If you wanted Photoshop CS2 for sketching or painting, Krita is a superior choice. Professional-grade brush engines. Seamless texture wrap-around tools. Free and open-source.
The version is a modified version of the software that does not require installation.