Several open-source communities provide (not pirated fonts) that download legal CJK fonts and configure F1–F5 mapping automatically. Search for “CJK Font Auto Installer” on GitHub. These are true “repacks” of configuration files, not font files.
If you are struggling with a specific PDF file, knowing or what language the document is in can help narrow down the best alternative font to use, and I can give you more specific advice on a replacement font . cid font f1 f2 f3 f4 f5 free download repack
Since "F1" in one PDF might be Helvetica and in another it might be a custom CAD font, there is no single "F1-F5" installer. there is no single "F1-F5" installer.