Hi there,
The alignment problem is causing by an empty paragraph in that first widget.
You can try to delete that or use this CSS:
.inside-right-sidebar .textwidget p {
margin-bottom: 0;
}
As for inserting the content in blog page, it’s an index page so you would have to use GP hooks:
https://docs.generatepress.com/article/hooks-overview/
http://demo.generatepress.com/hook-locations/
With conditional statement:
<?php if ( is_home() ) { ?>
content for blog page only
<?php } ?>