really bad website performance

hi all,
maybe somebody face the issue already. after i installed and enabled w3tc the performance of my website went down dramatically ??

GTMetrix load time from 3 seconds to 53 seconds. Once the page is cached it’s 1,7 seconds again.

Any help for me? Domain is: https://carostuttgart.de/

https://www.ads-software.com/plugins/w3-total-cache/