How to increase the level of image optimization using Gulp?

I have a task and would like to know how do I improve image optimization? Here's my script below:

gulp.task(
    'build-img',
    () =>
    gulp.src('assets/img/**/*')
        .pipe(imagemin( {
            interlaced: true,
            progressive: true,
            optimizationLevel: 2,
            svgoPlugins: [{
                removeViewBox: true
            }]
        }))
        .pipe(gulp.dest('dist/images'))
)

I read in the documentation going from 0 - 10 i level. But optimizations are static.