I keep getting an Apple ID verification code that I’m not sending

Someone may be trying to sign your Apple ID, which would generate the request for a verification code. Since you have 2 Factor Authentication enabled, as long as they can't access one of your trusted devices, they can't get a code and sign in. You should be okay.

Assuming you are using two-factor authentication, you can Check your Apple ID device list (https://support.apple.com/en-us/HT205064) and remove any device that shouldn't be signed in using the steps in the link.

If there are none that shouldn’t be signed in, then you should not have a problem at this point. But, if an unauthorized device signed in, Change your Apple ID password https://support.apple.com/en-us/HT201355 

Here is What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071

And see these security-related Apple Documents:

 If you think your Apple ID has been compromised https://support.apple.com/en-us/HT201303

Security and your Apple ID https://support.apple.com/en-us/HT201303

iCloud security overview  https://support.apple.com/en-us/HT202303

Ways to keep your information safe on Mac https://support.apple.com/en-gb/guide/mac-help/mh11402/mac

Using app-specific passwords https://support.apple.com/en-us/HT204397

You are welcome.