To remove your Threads account, go here. You'll have to delete your Instagram account, too.

How can your Threads account be deleted without also deleting your Instagram account? Hint: it's currently not feasible.

You cannot uncreate a Threads account after you have done so. It seems out that once you sign up for Meta, you are unable to erase your Threads account, at least not without also deleting your Instagram account. Therefore, if you joined the Threads train, it could be too late to alter your mind.

A statement in Threads' privacy policy states, "You may deactivate your Threads profile at any time, but your Threads profile can only be deleted by deleting your Instagram account."

This message does, luckily, also imply that you may terminate your Threads account without it having an impact on your Instagram account.