I noticed that current MESSAGE when installing ap24-php80-8.0.7nb6 from pkgsrc-2021Q2:
In order to use this module in your Apache 2.x installation, you need to
LoadModule php8_module lib/httpd/mod_php8.so
when used in httpd.conf will produce error:
httpd: Syntax error on line 174 of /usr/pkg/etc/httpd/httpd.conf: Can't locate API module structure `php8_module' in file /usr/pkg/lib/httpd/mod_php8.so: Undefined symbol "php8_module"
It seems Apache or PHP module is expecting now that LoadModule line should be just php without number as previous versions, so:
LoadModule php_module lib/httpd/mod_php8.so
is proper way of loading PHP 8 module, and then Apache is starting normally.