Everything is simple. Choose the most popular CMS. The most popular CMS is Wordpress.
Using Wordpress will protect you as much as possible from attachment to one programmer (the person who makes you a website). WordPress is absolutely free. He will not ask you to buy a professional version and extend the license for a year.
Everything is very simple in it. Even a person who is far from developing a website will be able to do the simplest things in it. There are many free and useful add-ons that will expand the functionality of your site. For example, it is very easy for anyone to make a form for sending messages, a callback or a photo gallery. The text editor is already installed, you can work with tables, lists, subheadings, and so on.
There are also a lot of people who understand WordPress on a more serious level. In any city you can find a programmer who will make you something individual. And you can find a person for remote work in a few minutes.
WordPress is ideal when you know that the project costs will be minimal, and you yourself are ready to do the main work on the site. For example, to create news or edit pages with services.
WordPress is ideal for business card sites. In fact, you can make much more serious sites on it. And don't believe that a WordPress site can't be promoted.
This is the traffic schedule of the "Legal Protection" website. It is made on WordPress. It all started with a business card website, and now it's almost 1500 pages, many sections and features.
When you are offered a paid site management system, they want to earn extra money for you. The most popular paid domestic CMS is 1c Bitrix. Web studios earn money on every copy of this product sold. If they start convincing you that this CMS is the best, then ask which major foreign projects use it? Your question is to make the Bitrix seller think.
Among the popular free CMS can be identified Joomla, Drupal and Modx. I myself prefer Modx for its versatility and ease of development. If WordPress immediately gives you a full-fledged website template after installation, then Modx is an empty white screen. A website on Modx needs to be made from scratch, but you completely control everything, do exactly as you want.
But Modx is not as popular as WordPress yet, although its share among other CMS is growing regularly. For example, this blog is made on Modx Revo.
TOTAL: if you don't want to be tied to a specific programmer or web studio, then choose the most popular CMS in the world. This is the only right choice.