Suas regras de reescrita originais parecem bastante simples:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteOptions inherit
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-s
RewriteCond %{REQUEST_FILENAME} !-l
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !^/index\.php
RewriteRule ^(.*)$ /index.php?$1 [L]
</IfModule>
Você já tentou usar o simples SEO / SEF .htaccess
como o que vem junto com o WordPress? Aqui está, mas adicionei a regra RewriteOptions inherit
da sua configuração original:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteOptions inherit
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>