The hard reality is that delphi ide is old and really buggy.
If we compare it to Intellij... No comment.
Currently, I use the plugin i-pascal for intelliJ (not perfect but far better than delphi for code navigation) Omnipascal is also very good.
It is precisely to avoid rewriting a plugin for each IDE that the language server is existing.
A delphi langage server will bring with one implementation, a support with majors editors / IDE or next gen web IDE as Eclipse CHE.