I tried to update as per Stephane’s instructions, almost everything worked.
The difficulties I encountered and I would say solved were
The old plugins were not visible in the “plugins” menu, I solved by downloading the new package with the wget and consequently I expanded them into the old folders of the plugins. At the end of the procedure, the system showed me the complete list in the marketplace menu.
I have revised the rh-php.ini file of rh-php73 due to the resignation limited to uploading and posting documents and files worth 500 MB.
The images of the user profiles were lost, so I had to restore them.
Many associated documents such as images, pdf documents, etc. probably did not open due to an external link to the file. In fact, by reloading the attachments, the GLPI server displays or downloads the newly uploaded files.
I had to re-execute the PC inventory, because the upgrade to the package did not take into account the inventoried data, but the list of computers was present. Therefore, I upgraded to the server for each PC.
At the moment everything works, including call notifications, then new ones, updates, etc.
upgrade from 0.90 (nethserver-glpi) to 9.5.7