How to make a 404 error for pages in a folder as well?

Question

htaccess

Hello. I have a site on bare html
in .htaccess code like this
RewriteRule ^index\.html$ / [R=301,L]
RewriteRule ^(.*)/index\.html$ /$1/ [R=301,L]
ErrorDocument 404 /404.php
works fine, if you go to a non-existent page site.ru/miss it will throw an
error.
but if the page is already in the
site.ru/page/miss folder, it
does not knock out an error.
I tried to write in ErrorDocument the full address of the page 404 ErrorDocument 404 site.ru/404.php
then everything works for all pages, but only with a redirect from a non-existent page to the site.ru/404.php page. Which doesn't suit me.
do not tell me how to make 404 for all types of pages?