How to get custom setting from get_option and pass it in getEntityRecords in gutenberg block?

As far as I can tell from looking into block editor store (you can use Redux devtools plugin for browser for that), entity for reading options is not registered. That means you cannot use getEntityRecord selector, which is usual way to obtain such data. Instead, either you can:

  1. Use apiFetch to fetch data from designated REST endpoint.
  2. Register your own entity to REST endpoint from 1. with addEntities and use getEntityRecord for getting data from option.