Answering your question is very difficult, if not impossible, for very specific reasons.
The Marazzi and Ragno companies are the same company, with the same factories that produce indiscriminately for both the brands. Apart from this purely commercial aspect, each Ceramic - including Saime - offers an infinite number of series that have substantial qualitative differences. Indeed, within the price lists of each ceramic we have very different prices of the same format, differences due to the difference of quality, since we always talk only about porcelain stoneware.
Therefore, since it is difficult to compare quality characteristics already within the same Ceramic, it is naturally impossible to compare products of different Ceramics.
The only thing we can suggest is to buy products from well-known brands, possibly making sure that they are actually producers of their products, such as those you have listed. Without being distracted by the misleading messages of non-branded products, cheap in price but often also in quality.