Hi @throwaway !
Welcome to the forum!
Nope
There are a few more technologies to consider for web dev.
The core technologies for the web would be HTML, CSS and JavaScript.
HTML is for content.
CSS is for style.
JavaScript is for the interactivity on the site. (When the user does something, like click a button, an event should happen)
Aside from those core languages you have what are considered libraries and frameworks.
These are tools that were built off of these core languages that make the development process easier.
CSS libraries and frameworks can include bootstrap, tailwind, bulma, material ui, etc.
Instead of writing custom CSS for all of your styles you can use a library and tap into their built in styles.
JavaScript libraries and frameworks would include React, Angular, Vue, Ember, jQuery, etc.
Instead of building applications all in Vanilla JavaScript you can use a library or framework to speed up the development process.
All of that would be considered client side which is what the user sees and interacts with.
You also have what is called server side which is the logic and brains behind your application. This is the code that the user does not see.
Examples of server side technologies and languages would include node, express, python, etc.
You also have databases.
This is where you data is stored for your web application.
For example, if you have an online store, then you would have a database of customers and orders.
Databases would include MongoDB, PostgreSQL, mySQL, etc.
You don’t need to learn all of this stuff because there is so much out there to learn.
But that gives you a rough idea of what web development is. 
There are times where you would want to use a website builder and then there are times where you want to hire a developer.
For example, if you have a coach that need a simple page for their little league team, you don’t really need a web developer for that.
A web site builder is just fine.
But if you have a business that is growing and needs custom software then you hire a developer.
I would suggest googling for salary information in your area.
For me, I am based in the States and living in a high priced state.
Starting salaries for junior web developers are $65,000 - 70,000 in my area.
For senior developers salaries are anywhere between $130,000 - 200,000+ in my area.
It really depends on location and the company you work for.
If you work for a FAANG(Facebook, Apple, Amazon, Netflix and Goggle ) company then you can make even more money then the average.
You would be looking at base pay, plus bonuses and stock options.
But those jobs are really competitive and hard to get.
You can google around for all of that information.
Hope that helps!