@Matt many thanks for assistance on this one.
Going further in my PHP8 debugging:
If I'm already logged in to the Admin panel and switch to php8, I can work fine.
But if I'm not logged in, and the site is set to php8, I get a PHP500 error.
The customer facing site works fine.
The log throws this.
PHP Fatal error: Declaration of IPS\hook592::parseTextForEmail($text, ?IPS\Lang $language = null) must be compatible with IPS\_Email::parseTextForEmail($text, ?IPS\Lang $language = null, $truncate = null) in /home/ddowdell/public_html/cheersandgears.com/init.php(913) : eval()'d code on line 66