Gulp 4: ExpressJs + BrowserSync + Nodemon + Sass Watching

gulpfile.js

const gulp = require('gulp');
const sass = require('gulp-sass');
const browserSync = require('browser-sync');
const nodemon = require('gulp-nodemon');

sass.compiler = require('node-sass');

// Sass compilation
gulp.task('sass', function() {
  return gulp
    .src('./sass/**/*.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest('./css'));
});

// Sass watching, depending on "sass" task
gulp.task('sass:watch', function() {
  gulp.watch('./sass/**/*.scss', gulp.series('sass'));
});

// Nodemon task:
// Start nodemon once and execute callback (browser-sync)
gulp.task('nodemon', cb => {
  let started = false;
  return nodemon({
    script: 'server.js'
  }).on('start', () => {
    if (!started) {
      cb();
      started = true;
    }
  });
});

// BrowserSync task:
// calls nodemon tasks and pass itself as callback
gulp.task(
  'browser-sync',
  gulp.series('nodemon', () => {
    browserSync.init(null, {
      proxy: 'http://localhost:3000',
      files: ['public/**/*.*'],
      port: 5000
    });
  })
);

// Dev Task: 
// Parallel execution of browser-sync/nodemon
// and sass watching
gulp.task('default', gulp.parallel('browser-sync', 'sass:watch'));

server.js

const express = require('express');
const app = express();

app.use(express.static('public'));
app.get('/', function(req, res) {
    res.send('Hello World!');
});

// Server Listening
app.listen(3000, function() {
  console.log('App listening on port 3000!');
});

Hi DevKitu, i'm sorry for this very late reply! Have you found the solution you're looking for?
In the meantime I'll try to answer what I can:

1. Strange that sass file aren't reloading, gulp watch should recompile every .scss file present in sass folder into css folder at every change (can you post the script section of your package json?)

2. It should always open on port 5000 if using nodemon/browsersync (server started with gulp command): your express/nodejs website si running on port 3000 and "forwards" (proxy) every call to port 5000 where browsersync is running (so that you can have live reload and all of browsersync functionalities).

3. If I remember correctly the public folder is the static folder of the website, I made this test using handlebars templates (instead of ejs ones) but still in the views folder, so it should be fine for you too.

Please let me know how are you starting your nodejs server (with what script), maybe this gist is lacking some parts on my end.