Hey, this isn’t a bug. “Use multiple models” is a Cloud/Background Agents feature for parallel best-of-N runs, and it’s not shown in local Agent/Chat by design.
In local chat, the closest equivalent is the slash command /best-of-n<model1,model2,...> <task> using git worktrees, you need a git repo. Example: Cursor 3: Worktrees & Best-of-N
You’re on the free plan, and Cloud Agents aren’t included, so that feature won’t work. You’ll need a Pro plan. Docs: Cloud Agents | Cursor Docs