Long loading time in some postings

Dear all,

three days ago, suddenly, some articles on my blog were no longer displayed. There was an error message from Wordpress in the frontend. After I replaced the "Easy Amazon Product Information" plugin with another Amazon plugin, the posts were displayed correctly again.

But now there is another problem: All of a sudden, some articles take an extremely long load time, more than 8 seconds according to PageSpeed Insights.

Example: https://www.maskenmagazin.de/ffp2-masken-kinder/

Other postings load at normal speed. Example: https://www.maskenmagazin.de/zettl-futurus-ffp2-maske/

I've deactivated all plugins without any changes.

Does anyone have an idea?