Did you notice this at the end of the restults?
In order to show you the most relevant results, we have omitted some entries very similar to the 29 already displayed.
If you like, you can repeat the search with the omitted results included.
Search console should tell you how much is indexed or not, and reasons why pages are not indexed, as in this topic.
Google makes a distiction between “Indexed” pages and “Not Indexed” pages. So Google does have a record of the non indexed pages, it just won’t put them in search results. So I believe the indexed pages are searchable.
The site is well over a year old, about 20 months.