Again CLS

Hi Spacetime, unfortunately I have again a problem with CLS. It was really really hard to find. I throtteled the speed down in Chrome DevTools to a very, very slow connection so that you can see loading of the page in slow motion and this happens:

AdInserter should load a placeholder with 350px in height after the first paragraph but on the load this placeholder is missing: https://imgur.com/a/rfrbJos
and shifts the index and the content down: https://imgur.com/a/uDNc1Tx –> https://imgur.com/a/MkUeDDg

How can I avoid that shift?

Greetings Kathrin

The page I need help with: [log in to see the link]