Fix security issue on WordPress contact form

My client has a Wordpress directory site. Each listing links to the same contact form template. We have a security issue as bots are able to complete and submit the form, so the listing owners get lots of spam. reCAPTCHA v3 is installed, but this does not stop all bots. I need a new solution to stop the bots getting through. I will supply the website link when we speak. See screenshot of form attached.