Hi, at the moment I cannot provide access to the site, I would have to "clean" it of sensitive data and it requires too much work.
Have you tried your plugin on a Joomla 4 installation? At the moment, on the test site, I use your Sj_joomshop model and as mentioned it does not work correctly. I tried to install the module also in the quickstart version of the model, also here, it doesn't work as it should (no zoom effect, wrong pagination, etc etc). So there is no need to give you access to the backend.
Please create the module demo in joomla 4
Thank you