Thanks for this, there doesn’t seem to be anything wrong with your feed configuration.
Changes are that, because of the big amount of products, the plugin is running into server configuration limitations. Did you already check the WooCommerce fatal error logs of the last few days to see if there are errors in there such as “maximum CPU/memory usage” errors and “maximum allowed execution time” errors?
When those errors are there I suggest you either increase those server limitations or you lower the plugin batch size from the default 750 products to, for example, 300 products per batch. This is how you can do so: https://adtribes.io/batch-size-configuration-product-feed/
Hope this helps?