How can I display content from tab that was active on save?
Add a text field OR boolean field to your content type, let's call it "Active Tab".

Using jQuery you can make it when tab x gets clicked, it auto fills the text field OR auto checkmarks the x boolean box. (You can hide this field with CSS if you want). 

Use a template file to control the display/output. So simply in your twig template file perform an conditional statement

{% if content.field_active_tab.0 == 'x' %}
  {{ content.field_something }}
  {{ content.field_something_else }}
{% endif %}

{% if content.field_active_tab.0 == 'y' %}
  {{ content.field_something2 }}
  {{ content.field_something_else2 }}
{% endif %}