I want to secure my account using 2FA.
This will be an optional feature
Workaround
You can link your Koinly account to your Google account, effectively enabling 2FA (assuming you have it set up on Google). See section "How to switch to Google login" in How do I change my email or login method? | Koinly Help Center
Mind that, after linking your Google account, your password will be removed and you will no longer be able to log in using the email/password combo - only via "Continue with Google"