WordPress is a core Blog platform, and has been extended to a CMS platform.

WP was a blog platform that has been extended to be a full CMS, it is light and can be fast with better SEO possibilities.

WP is well supported, and the latest usage is approxamitly 30% of the market.
WP works well on LAMP stack.
Trade-off's; aging platform core, WP will have a difficult time with future core improvements and to use newer technology, what makes WP good, is also its weakness. Poor media features. Needs lots of plugins to add features, some that should be core features, like Widget management, media directories/organization, security issues with increased use of plugins.

The roll out of Gutenberg showed the issues with attempting to improve WP core features, and future issues with improvements.

I recommend the best platform that supports the client's requests and requirements.

Both platforms have improved and have some pro's and con's about them, they are more similar than different.

I see many clients looking to migrate to WP from Joomla, Wix and Squarespace, also see requests WP to Wix and Squarespace migration, but very few to migrate to Joomla.

I also see more request on security issues with WP due to lack of updating, old PHP, and bad plugins, this is also since it is increasing in use over 30% of projects. Like any platforms it has to be done with correct procedures/processes and maintained.

WordPress MU (multisite):

WordPress offers a multisite capability (2 or more integrated projects) that can be used to improve management of your network of WP projects. Already existing WP projects can be configured as a WP MU, and they can be seperated as individual projects if needed.
There can be pros and cons that can also determine if a WP project can be configured or added to a WP MU project.
Compatability of plugins and themes is one critical requirement. Some solutions are not always WP MU compliant, many of them are, and some are a commercial solution. Depends on the vendor and solutions used. Make sure those WP elements are WP MU compliant.

 Check out the requirements and advantages to use or convert your netwro of WP projects.

WordPress Plugins:

Page Builders:

For the design and layout of your WordPress projects the direction is using a Page Builder plugin with your theme. There are several to choose from that offer a range of solutions and pricing.