Which is the best alternative to Wordpress?

For the most part, I always recommend WordPress (self-hosted) because they OWN the website and files. With Wix & Square Space they do not although I think you can export as HTML code.

I think this question all depends on what you are wanting to do, aka who is the client you are wanting to build a website for, and what capabilities do they want on a website. If the said client has more than 5 pages and eCommerce + some other special features I would 100% go with WordPress as it is so customizable, you can use the plug-ins or insert your own code to customize just about anything. But if this customer just wants a very simple website with straightforward information I don't see why Squarespace would not work. They do limit what you can do layout-wise, so maybe buy a template on the creative market if you want it to be a little more unique from just their standard templates, and out of all the platforms like Squarespace I like it the best for my freelance customers because I can sign them up and design their site free any cost for 10 days before Squarespace wants any kind of payment (which you can build into your contract with the customer so you pay nothing upfront) the other reason its great for freelance customer is that when you hand the site over its done, they have complete access to the back end that you can teach them to use, all of their monthly billing is in one place which is also nice. But the long of short of it is, it all depends on what site your making and how complicated it is because if it breaks a traditional template at all i would go with wordpress.

If you're looking for ease of use then it's hard to beat WordPress unless you go with a solution like Squarespace or Wix which severely limits what you can do. The top alternatives to WordPress really are about increasing your ability to customize and as such are much more difficult to maintain and the editing experience is a significant step back from WordPress especially with Project Guttenburg, Elementor Pro, Genesis Pro or one of the other visual editors being used. That said if you definitely want something different many agencies use CraftCMS (also open source) for its speed and simplicity. The more "enterprise" solutions like Drupal, Joomla, etc are a nightmare to use and maintain and I highly recommend against them.

WordPress (notice the camel casing) is fairly easy to learn to use and there's numerous resources that can help you along the way. The power in WordPress is the sheer numbers of users. Over a 1/3 of the internet is powered by WordPress. It's used for everything from blogs to ecommerce stores to complex booking websites. Sure, there's Content Management Systems that have a smaller learning curve, but there's always something that's sacrificed for ease of use (usually the ability to customize or add functionality). If you're looking to make WordPress easier to use, I'd suggest pairing it with a plugin like BoldGrid or BeaverBuilder. These plugins (plugins add functionality to WordPress core) allow you to build good looking websites quickly. As an alternative to WordPress, there's plenty of CMS's like Joomla and Drupal, but they are equally challenging to use if not harder than WordPress. There's closed source CMSs like Wix, Weebly, and SquareSpace but I'd caution against them as there can be nuances that do not allow for portability and expansion.