error 404 for domain redirects to blog in subdirector help with .htaccess please

Hello Help Angels,

My blog is in a subdomain /petblog

When I upgraded recently and lost my permalink settings I reset them to default and then pack to how I wanted them.

I have created an error 404 page for my domain which was coming up when my permalinks weren’t working. I got a note when I corrected to change my .htaccess file to the following:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /petblog/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /petblog/index.php [L]
</IfModule>

which I added to the error 404 command like so:

ErrorDocument 404 https://www.vivbounty.com/vb_404.html
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /petblog/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /petblog/index.php [L]
</IfModule>

But now my entire domain redirects to a page not found within the petblog.

I would like it the other way around so that any pages not found on my main domain re-direct to my error 404 page.

Can anyone help?

Thanks in advance