Best database for Unity targeting Android and iOS

I'm looking for a database asset to be used on Android and iOS that needs to store text for language references.

I need to provide a search bar feature so as the user types the database is read and starts to autofill with possible entries.

So the word list could be anywhere up to 500k entries so would it be best to use an ordered list or an sql database?

As the user types is it more efficient to search a list by entered character count or to search a database?

Any pointers please?

Thanks