Subpage is redirecting to spam site

My Wordpress site has recently been hacked and I followed the steps described here to clear it: https://wordpress.org/support/article/faq-my-site-was-hacked/

The whole site redirected to a spam website. Now I can access it and the backend again. But still there is one single page which is still redirecting to the spam site and I cannot figure out why.

The odd thing is as soon as I am logged in to Wordpress I can access the page. As soon as I am logged out the page redirects to the spam site.

But only this particular page. All other pages are working perfectly fine.

I have already searched through loads of php-Scripts to find something which doesn't belong there. I have installed different security plugins and scanned the whole Website several times. But no luck.