Unfortuanetly there is a very large increase in spam lately across the board. What you can do however is to ensure you are doing the following
Ensure you are using hCaptcha, rather than any other captcha type. This seems to be the most effective at present
Ensure you have increase the sensitivity when you set up an hCaptcha account
Ensure you have question and answers set up, as you dont seem to have at present
You can see more about this, and how to use the "Mark as spam" function, which will allow you to delete all the posts from a person at once if needed, in the following guide