Currently, it is possible to set Language Clients via the Language Client Manager to start their servers once per project with BaseSettings::RequiresProject.

For qmlls to be able to be managed by LanguageClientManager, it would need a way to be enabled/disabled in a project specific manner.

Maybe the LanguageClientProjectSettingsWidget class & friends could be extended to enable/disable "per project" language servers on the current project with an extra checkbox?