Help With Contact Form Abuse - a Trivial solution

there is the honeypot approach that CI4 makes available to you . As i understand it robots will be able and do fill in every form even hidden from human eye ones. I do it by adding <input type="hidden" name="honeypot" value=""/><br>

to forms , then tweak Honeypot.php as required located app/Config/Honeypot.php

CMS CI4 A CMS system, runs out of the box written on top of CI4

Arch Book  CodeIgniter4 on Apache(pages 92-114) 

CI4-CMS Github