Yes, for prototypes, MVPs, temporary chaotic storages.
NO MongoDB for production workloads. No MongoDB for more than 1000 records in one collection. No MongoDB higher 4.0.3.
There are several nice apps for RSS feeds, but unfortunately, the low support on OS level makes RSS comfortable for geeks but not for ordinary people, who now mainly consume content in Twitter and Facebook whose feeds btw is a centralized and more comfortable version of their ancestor - RSS.