Zend certified PHP/Magento developer

Store views are showing 404 after upgrade to Magento 2.4.3

After upgrading from Magento 2.2 to Magento 2.4.3, I’m getting 404 error pages for 10 store views (e.g. mydevdomain.com/pub/de/) and only our international store views are working (EN, AR).

I’ve switched to Luma theme and the same is happening, though our 2.2 store views are good and we didn’t experience this issue in previous upgrades.

Please help. Thanks in advance.