The getUser method should be making a call to the userinfo endpoint and, provided the token you are sending to the endpoint was issued to an end-user, the ‘sub’ value returned should be the user’s ID in your Okta org, see the example in our docs here.
If you log into your application, grab the raw JWT ID token (you can find it stored in Local/Session/Cookie Storage, depending on which you chose but local should be the default, with the key okta-token-storage), and decode the token, do you see the user’s ID as the sub claim value?
Yes, I see it now. My fault, the client id, and the user id were very similar, except for 3 characters. After, decoding it, I was able to compare the values.