Doing exactly the opposite is also a right approach:
Absorb as many features as possible, so that more people will be gravitated into a centralized place. For bugs, if the original feature submitter isn't around, potential new maintainers will emerge and fix them.
Jabref, which use .bib file as storage. The importing features are almost the same (all major sources supported). Tagging and note taking are nice. Full text search is implemented with the mighty lucene. Word plugin and Browser import plugin are good too.
Both zotero and jabref are on similar level of simplicity. However, they are very different on details if you use them heavily.
Kate has LSP support for a few years already.