.htaccess redirect without changing URL - .htaccess

Question

The content is currently accessed through this URL: http://website.de/de/angebot/llm
On our brochures we would like to print the short URL for our customers, so the above URL can be accessed when entering short URL like this: http://website.de/llm
This is what I got so far:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^/llm http://website.de/de/angebot/llm [QSA,NC,L]
It works in the way of redirecting clients. So when they enter short URL they are properly redirected to long URL.
What I would like if it is possible that URL doesn't change to the long one, but stays short in their browsers.
This is the full .htaccess
# Exploits
RewriteCond %{QUERY_STRING} base64_encode[^(]*\([^)]*\) [OR]
RewriteCond %{QUERY_STRING} (<|%3C)([^s]*s)+cript.*(>|%3E) [NC,OR]
RewriteCond %{QUERY_STRING} GLOBALS(=|\[|\%[0-9A-Z]{0,2}) [OR]
RewriteCond %{QUERY_STRING} _REQUEST(=|\[|\%[0-9A-Z]{0,2})
RewriteRule .* index.php [F]
#Custom
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^/?llm de/angebot/llm [NC,L]
# Joomla
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteCond %{REQUEST_URI} !^/index\.php
RewriteCond %{REQUEST_URI} /component/|(/[^.]*|\.(php|html?|feed|pdf|vcf|raw))$ [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule .* index.php [L]

Answer 1

With joomla you could create a redirect within joomla that would help you achieve this.
You could as well create a menu item as an alias to your long url.
In .htacess I would try something like:
RewriteCond %{HTTP_HOST} ^yourdomain.com/llm$ [NC]
RewriteRule ^$ http://www.yourdomain.com/de/angebot/llm [R=301,L]