If you want to become a full-stack developer, you need to know HTML, CSS, JavaScript along with a backend but making the right choice in an era where there are a lot of options creates a lot of confusion for newbie developers.

The Bucket Technique
As a part of this technique, we will study each technology just enough to start building sites.
My breakdown for frontend and backend development is as follows:

FrontEnd Development:

➔ HTML
➔ CSS
➔ JavaScript
➔ Database (Insert, Update, Delete)

After you finish learning all these technologies, you will be able to build good designs but it is not possible to build a stunning website without graphic designing skills. You need to either be a good designer or refer to some design that is good enough for your site to look amazing!
For that, you can either refer to some websites which are already built by great designers or refer to my curated list of free design resources for developers here.

Backend Development

I recommend the following options from a huge list of available options with pros and cons:

1. PHP - Easy to learn, best for beginners, limited support of libraries
2. NodeJs - JavaScript which you already know from the frontend, Difficult to learn JavaScript concepts like callbacks are used
3. Django/Flask (Python-based backend Frameworks) - Includes ORM, great set of python libraries, need to learn python

Not recommended for beginners

1. Frontend frameworks like react, vue, angular
2. Third-party JavaScript, CSS frameworks
3. Website builders

Don't get me wrong here. JavaScript frameworks are amazing but if you want to be a successful web developer, you need to master HTML, CSS, JavaScript first
Tools every Web Developer should know about
➔ UX wing for Icons
➔ PixaBay for free Images
➔ FreeHTML5 for free templates
➔ Unsplash for Image API
➔ JSON Placeholder for fake Online REST API
➔ More resources are available here

If you wish to learn from videos on the internet, this would be my best recommendation: https://teachyourselfcode.io