I have a client that wants to pass the web that has been made with Joomla to WordPress but keeping all the information that it has in it and in the same domain, what is not how it can be done because if it were from a domain to another with a plungin I can do it.
There is a plugin called FG Joomla to WordPress. With this plugin you can migrate everything without losing information, the problem is that you will have to make many changes.
Another idea that I have used (if the page is not too complex), is to use httrack link
With this program you download the full site html and then install it in wordpress.
Unfortunately, it will not work in case you need to migrate a woocommerce, for example, but if your client has 4 pages (say) and a lot of photos.The trick will be how to configure the HTTrack program