Hello,
The thing is that the default content was edited via Elementor therefore you need to re-edit it via Elementor also. First of all, navigate to Elementor -> Settings -> General -> enable the “Posts” post types.
https://prnt.sc/zL_-_J0O-X45
After that, edit the blog’s content via page builder and it will replace the old content.
https://prnt.sc/xIpnEvyuVAd0
If you ever need to reach out to me, please do not hesitate to do so.
Kind Regards