It’s not too hard to disable all of it

{
  // Disable Telemetry
  "telemetry": {
    "metrics": false,
    "diagnostics": false
  },
  // Disable Assistant:
  "assistant": {
    "enabled": false,
    "button": false,
    "version": "2"
  },
  // Disable Copilot:
  "features": {
    "inline_completion_provider": "none"
  },
  // Disable Collaboration Features:
  "collaboration_panel": {
    "button": false
  },
  "chat_panel": {
    "button": false
  },
  "notification_panel": {
    "button": false
  }
}

Vikunja (hosted on tchncs: https://todo.tchncs.de/) is great for tasks but I haven’t tried using it for a grocery list.