Replace /Volumes/MyUSB with the path to your USB drive.
Even if you find a clean DMG, High Sierra has a notorious “Gatekeeper” issue. Because the certificate on the installer expired in 2019, macOS will flag any copy downloaded today (even from Google Drive) as “damaged.” You have to manually change your system date in Terminal to install it. Most Google Drive copies do not include these instructions, leading to hours of frustration. --- Macos High Sierra 10.13.6 Dmg Google Drive