Why doesn't redirect to 404 work in .htaccess?

Question

Apache HTTP Server

It is required to rewrite to /404 for all non-existent files/folders on the server, except for static files (css, js, etc.). I've already tried dozens of options, it doesn't work anyway. I already memorized the first 10 pages of Google results on the problem. For example:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(css¦jpg¦gif¦zip¦js)
RewriteRule . /404 [L]

If you try to do the opposite, so that only non-existent files / folders with a certain extension are sent to /404, then everything works

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} \.(xml|txt)$
RewriteRule . /404 [L]

Worth adding! and no rebound effect from ! does not work as expected, In general, this rule seems to disappear with !.
All the same, a 404 rewrite is done for requests with .css, etc. at the end, although it is clearly written not to do it.

Answer 1

Isn't it easier ErrorDocument 404 /404?

Answer 2

¦What is this symbol. You also need to indicate that with your config, this will not be a normal 404 error, but will only display a page with that name.
How to redirect Apache before it gives a 404 error?

Answer 3

Shouldn't non-existent statics (css¦jpg¦gif¦zip¦js)lead to a redirect?
If it should, then, as IceJOKER said, ErrorDocument 404 /404, only up to RewriteEngine on.