Question

I’ve tried a number of things… I know I’m missing something. Help!!

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^\? - [R=404,L]
</IfModule>

Answer 1

RewriteRule does not work directly on query strings, you have to use RewriteCond to access them (or tricks on internal rewrites, but that’s not necessary here).

Try

RewriteCond %{QUERY_STRING} .+
RewriteRule ^/?$ - [R=404,L]

Any request to the root path with a query will end in a 404 response.