Hi there,
Sections is an old Module, that we don’t really recommend for constructing pages since the Block Editor.
Instead we recommend using the Block editor with our Block Plugin: GenerateBlocks for creating this type of layout:
https://wordpress.org/plugins/generateblocks/
And yes you can use this method on Posts.
Couple of issues are related to the Post meta – as they will be output in the full width container if your apply this: Layout Metabox > Page Builder Container set to Full Width
– but we can assist with fixing that. If you need help with that please raise a new topic.