Vita3K requires specific font files to display text correctly in games:
Even with the fonts installed, you might run into issues. Here are quick fixes: free download font package vita3k exclusive
Load any previously problematic title. The text should now be crisp, clear, and fully readable. Vita3K requires specific font files to display text
There is no official "exclusive font package" for Vita3K. The emulator uses standard system fonts that come from a real PS Vita's firmware dump. Distributing these fonts separately would be copyright infringement. There is no official "exclusive font package" for Vita3K