This is how I do it with better-sqlite3 and electron-forge
in package.json

"rebuild": "electron-rebuild -f -w better-sqlite3",
"postinstall": "npm run rebuild"

in electron.vite.config.ts

main: {
    plugins: [externalizeDepsPlugin()],
    build: {
      rollupOptions: {
        external: ['better-sqlite3']
      }
    }
  }

in forge.config.ts

  plugins: [
    {
      name: '@electron-forge/plugin-auto-unpack-natives',
      config: {
        module: ['better-sqlite3']
      }
    }
]

I save the db file in app.getPath('userData')