Gulp + BrowserSync how to optimize Gulpfile.js performance?

Question

gulp.js

Gulp + BrowserSync how to optimize Gulpfile.js to avoid multiple page reloads and complete copying of immutable files?
gulpfile.js:

'use strict';

const gulp = require('gulp');
//const scss = require('gulp-scss');
const less = require('gulp-less');
const sourcemaps = require('gulp-sourcemaps');
const debug = require('gulp-debug');
const gulpIf = require('gulp-if');
const del = require('del');
const browserSync = require('browser-sync').create();
const notify = require('gulp-notify');
const cssnano = require('gulp-cssnano'); // Подключаем пакет для минификации CSS
const csso = require('gulp-csso');  //для минификации CSS
//const uncss = require('gulp-uncss');    //для оптимизации CSS файлов, анализирует HTML код и находит все неиспользуемые и продублированные стили
const concat = require('gulp-concat'); // Подключаем gulp-concat (для конкатенации файлов)
const combiner = require('stream-combiner2').obj;
const uglify = require('gulp-uglify');

const isDevelopment = !process.env.NODE_ENV || process.env.NODE_ENV == 'development';

gulp.task('styles', function() {

    return combiner(
        gulp.src(['frontend/styles/fonts.css','frontend/styles/main.css']),
        gulpIf(isDevelopment, sourcemaps.init()),
        //less(),
        //cssnano(),    //минимизируем
        concat('main.min.css'), // Собираем их в кучу в новом файле main.min.css
        // uncss({
        //     html: ['index.html']
        // }),
        csso({
            restructure: false,
            sourceMap: true,
            debug: true
        }),
        gulpIf(isDevelopment, sourcemaps.write()),
        gulp.dest('public/css')
    ).on('error', notify.onError());

});

gulp.task('librarys', function() {

    return combiner(
        gulp.src(['frontend/styles/lib/*.*']),
        gulpIf(isDevelopment, sourcemaps.init()),
        cssnano(),    //минимизируем
        concat('lib.min.css'), // Собираем их в кучу в новом файле lib.min.js
        gulpIf(isDevelopment, sourcemaps.write()),
        gulp.dest('public/css')
    ).on('error', notify.onError());

});

gulp.task('scripts', function() {

    return combiner(
        gulp.src(['frontend/assets/js/lib/*.js']),
        gulpIf(isDevelopment, sourcemaps.init()),
        uglify(),  //минимизируем
        concat('lib.min.js'), // Собираем их в кучу в новом файле lib.min.js
        gulpIf(isDevelopment, sourcemaps.write()),
        gulp.dest('public/js')
    ).on('error', notify.onError());

});

gulp.task('clean', function() {
    return del('public');
});

gulp.task('assets', function() {
    return combiner(
        gulp.src(['frontend/assets/**']),
        gulp.dest('public')
    ).on('error', notify.onError());
});


gulp.task('build', gulp.series(
    'clean',
    gulp.parallel('styles', 'librarys', 'assets', 'scripts'))
);

gulp.task('watch', function() {
    gulp.watch('frontend/styles/*.*', gulp.series('styles'));

    gulp.watch('frontend/styles/lib/*.*', gulp.series('librarys'));

    gulp.watch('frontend/assets/**/*.*', gulp.series('assets'));
});

gulp.task('serve', function() {
    browserSync.init({
        server: 'public',
        notify: false,
        reloadOnRestart: true,
        snippetOptions: {
            rule: {
                match: /<\/body>/i
            }
        },
        reloadDebounce: 2000
    });

    browserSync.watch('public/**/*.*').on('change', browserSync.stream({once: true}));
});

gulp.task('dev',
    gulp.series('build', gulp.parallel('watch', 'serve'))
);

gulp.task('default',
    gulp.series(gulp.parallel('watch', 'serve'))
);

Those. I change the class name of the block in Index.html and get:

[15:57:11] Starting 'assets'...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] File event [change] : public\fonts\roboto-v16-cyrillic-ext_cyrillic_latin-300.svg
[Browsersync] File event [change] : public\fonts\roboto-v16-cyrillic-ext_cyrillic_latin-300.svg
...
[Browsersync] Reloading Browsers...
[Browsersync] File event [change] : public\img\check-in.png
[Browsersync] File event [change] : public\img\check-in.png
[Browsersync] File event [change] : public\img\doc1.png
[Browsersync] File event [change] : public\img\doc1.png
...
[Browsersync] File event [change] : public\img\trader.png
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] File event [change] : public\fonts\font-awesome\css\font-awesome.css
[Browsersync] File event [change] : public\fonts\font-awesome\css\font-awesome.min.css
[Browsersync] Reloading Browsers...
[Browsersync] File event [change] : public\fonts\font-awesome\fonts\fontawesome-webfont.svg
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[Browsersync] Reloading Browsers...
[15:58:21] Finished 'assets' after 1.17 min

Finished 'assets' after 1.17 min
What to change in gulpfile? Can gulp.task('watch' be specified somehow?