I think a property should be added to set the Search Widget or Layer Search Source to limit the search using the like operator so that the query would be <searchField> like '<searchTerm>%'. The prefix and suffix properties won't work for this.
I am using a feature layer search source with the Search Widget. The feature layer contains address points that have addresses with apartment numbers. There are some single digit address numbers, such as 8 Wyclow St. When users enter 8 into the input box, the top 6 suggestions do not include 8 Wyclow St or even, for example, 8000 Main St. Instead the top suggestions presented are addresses with the character '8' elsewhere in the address text.