After these changes, there were no logs related to Solr or DB query and not getting any documents on UI.
After seeing the code of the DbOrIndexSwitchingQueryLanguage class, found that hybridEnabled attribute should be true for executing this case. Can anybody suggest me how to set hybridEnabled true if this fixes my problem or suggest anything else to resolve my use case?
Re: How to set hybridEnabled true in DbOrIndexSwitchingQueryLanguage alfresco solr?
It looks like you have already looked into the source code, so you might have seen the property solr.query.hybrid.enabled used to configure to property you mentioned from the DbOrIndexSwitchingQueryLanguage class.