Hi,
These warnings are indeed linked.
Because the import is not able to access the URL of the images you have in your CSV, and because you're on PHP 8.3, PHP is more strict with the call to array_change_key_case and stops the process with that error instead of just rolling with it and just skipping the file with a warning.
I've just added a patch on our end to remove the error. So you can update your HikaShop to get the patch. But it might be better to just add the missing images or fix the URLs in the CSV file so that the proper data is imported.