Incorporate data from other sources
First, let me say that this database is an amazing resource, I love it.
However, product availability, while surprisingly good, still appears to be lacking in my experience. I scanned all the products at my house, and only 1/3 were already in the database. Of course, I can add those products, and then they would be available for everyone.
But, there are also corporations, some of them affiliated with governments, that do have complete data about these products. For example, the app 'Mijn Eetmeter', made by the Dutch government, has no issue recognizing all products at my house. They can do this because they are affiliated with the logistics company GS1, which is the de-facto bar code supplier in the Netherlands.
So, have you considered incorporating data available from sources other than manual input? GS1, specifically, does not seem to provide free access to the data, but with a collaborative effort, it may be possible to get the Dutch government to provide access to the data. Or their app 'Mijn Eetmeter' could be scraped.
Marvin M. commented
We already provide extra tools for importing multiple items at once. See here https://de.pro.openfoodfacts.org/ for example iglo and ferero have added some products. Cooperating with the Dutch government is a great Idea, I'll pass that on.