I’ve discovered one interesting fact.
No matter what value I put in is_in_stock field (In Stock, Out of Stock), even if in backend you can see the products (even more, if I set it as “In Stock” backend product details show it as In Stock, the frontend does not load the product.
I think this is because cataloginventory_stock_status table is not populated with values.
I compared an imported product with a backend created/modified product and the difference is, 1st one does not insert values in this table, second one (even if u create one from scratch or you edit one that you have imported by switching back and forth the “is_in_stock” value) has records in this table.
Many thanks in advance.
P.S. The csv sample I uploaded in my 1st post is still valid. No changes made.