It is by design that we rely on ElasticSearch to deliver search results. And yes we accept the fact that search results can be not 100% sync for some millis. On the other hand queries execute blazing fast (even one tremendous data sets) and allow very powerful google like search terms.
If you need a rock hard, 100% sync at anytime, persistency solution - BusinessData is maybe not the feature you are looking for. Just use JPA (ivy EntityClass) or any other persistency technology you like that relies on classical (often slow and inconvenient) relational database schemas.
And of course you already mentioned it by yourself. Our BusinessData set is always consistenly saved. And therefore you have access to them e.g. by Id. But search features could take some millies to deliver accurate results.
I think it is very unlikely that one would favor a 100% up to date search result over the benefits of a powerful query engine. Unless you are implementing a stock broker service. But maybe you can share your use-case....