IP whitelisting and two-factor are managed at the Workspace level in Bitbucket. From the wording of your question, it sounds like you may be looking at the configuration for an individual repository. Let's walk through going to the workspace settings and enabling these security features:
In the off chance that you still can't enable these security settings once you're in the Workspace settings, we'll need to have you open a support case to take a look at your account. However, I think the most likely culprit is being at the repository level rather than the workspace level.
Daniel | Atlassian Support
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