Redirect to folder only if root from other site referrer

Question

I have a redirect from root to subfolder. If user visits https://example.com it redirects to https://example.com/subfolder. But I want it not to redirect if referrer is my site, so user can reach root page.

For example:

1. User visits https://example.com
2. It redirects to https://example.com/subfolder
3. User visits https://example.com/subfolder/file.html
4. there's a link on this page to https://example.com and he follows it
5. It must open https://example.com and not to redirect

Here is my .htaccess:

RedirectMatch ^/$ https://example.com/

Please, give me an advice to solve the problem, I'm poor on .htaccess rules.