I am not 100% sure but I guess:
When you put:
AddHandler application/x-httpd-php81 .htm .html
into
.htaccess your .htm, .html files are handled by suPHP. That is why you see
Server API: CGI/FastCGI
To solve this you need to customize the Apache template file (you wrote about .htaccess that is why I am sure you use Apache
).
The Apache php-fpm template files are located in the folder:
/usr/local/cwpsrv/htdocs/resources/conf/web_servers/vhosts/httpd/php-fpm/Probably you need to change the lines:
<IfModule proxy_fcgi_module>
<FilesMatch \.php$>
SetHandler "proxy:%backend_fcgi%|fcgi://localhost"
</FilesMatch>
</IfModule>
inside the template files to something like:
<IfModule proxy_fcgi_module>
<FilesMatch \.php$|\.htm$|\.html$>
SetHandler "proxy:%backend_fcgi%|fcgi://localhost"
</FilesMatch>
</IfModule>
then rebuild virtual hosts and restart Apache.
Sorry, I use a free version of CWP on my test box, so I don't use php-fpm there and can't be sure it is 100% working solution (make backups before you modify something
).