Please rekook my questins one again.
Regarding iFrame. You probably havent noticed the further problems with it. See on linked site Tab2. If iFrame is inside Tab, its covering following modules and following sections are on top of the iFrame. Such behaivior is probably not intended ?
With custom css it can be changed, if .sppb-tab display: flex; is changed ----> display: block; I actually dont why it should be now flex , as it was in 3.xxx always set as "block"
I have created a page with Carousel Pro , SPPB 5.0.6, default editor TinyMCE. Also here is created garbage p .
Further details in the hidden area of the previous post.