sulu VS TYPO3

https://sulu.io/ or https://kunstmaancms.be/ if you want to stay with symfony. Both solid options

I want to try Sulu first because it is Symfony-based.

Another usecase are Framework based CMS System. Beside Drupal, Typo3 using example Symfony components, still are not Full Stack Symfony and don't use Symfony based folder structure and are so very different then using Symfony Full Stack based CMS. In this area other CMS like Sulu, Bolt, .. are placed which do not hide Symfony Full Stack and are more for the web applications which are not typical just a Website but has application based component in it which can be build with the Symfony components and ecosystem. This CMS are also mostly more version control friendly as most configurations are inside Code and not inside Database and the CMS admin concentrate on Content Management and configure the System itself. Another CMS which is more and more migrating Full Stack Symfony is Contao CMS, which definitly should not be forgotten.

Try something on Symfony. For example https://github.com/sulu/sulu. It's a CMS, but I've noticed that it has some domain-driven design principles implemented.

While I was working on Sulu CMS and did invest a lot about prototypes around Hexagonal Architecture. I did miss something specific in the PHP-Fig interfaces, a Interface for Template engines.

I doubt that WordPress is in danger. Its multiverse / flexibility and ease of use compared to real content management systems like Typo3, NEOS or Drupal, and the ability to just install it and control your content on your own webserver, try that with Wix, WebFlow, SquareSpace, Shopify and all those "serverless" software as a service servers. Hopefully, the core team will either get their block editor right some day (WordPress 7.0?) or make it completely optional. That would still be better than a fork, but I'd wished they had improved security, performance and internationalization instead of releasing the new editing features in an unstable beta state.

In a more business feature based CMS but still more like traditional CMS are Typo3 and Drupal, both have there usecase and sure a big community around them with a lot of modules and co. And both allow customization and building, installable plugins and themes. But modern version allow give more control from the system to the dev. We also should not forget of Typo3 called Neos CMS, which has its own way and Framework around it.

The official site of TYPO3 https://typo3.org/.

It depends on how you installed your site. Is it composer installation or did you download the files from the typo3.org? If composer based - did you use helhum's secure installation?

Content management products using Statamic and TYPO3

At this point I'll try to show 5 important new tips I've learned myself while working on client projects with the TYPO3 CMS.

Official TYPO3 Repository