This is useful if you have multiple instances of Kate open, each on a different project; clangd takes 10% of my 16GiB of RAM per project (depending on project's codebase size). It would be nice if there is a way to "suspend" the LSP server, i.e. terminate it to free the memory, the one can resume/start it again when one wants to work on the project in that Kate instance. Closing the Kate instance is an option, yes, but quite annoying, you have documents open, edits in the undo stack ...etc.
Another data point, QtCreator has two config options: - "Files to keep open": "Minimum number of open documents that should be kept in memory. Increasing this number will lead to greater resource usage when not manually closing documents." - "Auto-suspend unmodified files": "Automatically free resources of old documents that are not visible and not modified. They stay visible in the list of open documents."