Class "JError" not found after updating Joomla 4 / Joomshopping 5

Class "JError" not found after updating Joomla 4 / Joomshopping 5

Hello,
I updated Joomla and Joomshopping to the latest versions (also all addons for joomshopping) but whenever I switch to the shop, I get the Class "JError" not found message.

Website URL: https://www.blumerie-immergruen.de
Shop URL: https://www.blumerie-immergruen.de/index.php/shop/category/view/2

Edit:
Debug screen added

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Aw: Class "JError" not found after updating Joomla 4 / Joomshopping 5

need update all module / plugin / addon

Aw: Class "JError" not found after updating Joomla 4 / Joomshopping 5

Alright, I checked and updated / deactivated all plugins /addons / modules. The shop kinda works now but when I click on a product to switch to the product site, I get another error message (see screen attached).
It seems to be a problem with some Zoom_image Addon but it's not even installed...???


Edit:
I deleted the constant in the product_simple.php but then comes another error message...there seems to be a bigger problem still.

I would really appreciate it if we could make the shop up and running again.

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Aw: Class "JError" not found after updating Joomla 4 / Joomshopping 5

old template for product
https://www.webdesigner-profi.de/joomla-webdesign/shop/templates/detail-product---text-right.html?lang=en

Administrator / products / edit
Set Template "default"

Aw: Class "JError" not found after updating Joomla 4 / Joomshopping 5

Ok, i downloaded and installed the latest version of the template although it doesn't seem to be for Joomla 4 nor joomshopping 5.x???
Where should i change the template to default? The template is already set to default, if that's what you mean (see screenshot)

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Aw: Class "JError" not found after updating Joomla 4 / Joomshopping 5

Administrator / products / edit
Set Template "default"