As of 2025, Gangnam 1970 has not received an official 4K UHD release. Any "4K REPACK" is likely an upscale with fake subtitles. Stick to 1080p Blu-ray sources.
Before you search for a download, ensure you know which video file you have. Subtitles are not universal. Here is a checklist: Gangnam 1970 English Subtitles Download REPACK