A family of Microsoft word processing software products for creating web, email, and print documents.
The ribbon interface was formally introduced as the "fluent" ribbon. It reforms depending both on its content (the added groups) and window size and resolution.
Groups change into menus. You already notice the reforming between your two monitors. You can get some of the same effect by reducing the window size on a single monitor.
The Classifications group is from a local customization, probably an Add-In. The Acrobat group is from an Acrobat Add-In.
These imagers are my current Home tab with Ribbon tabs showing.
The group on the left was created through XML formatting and replaces the clipboard and editing groups. The template for this is a sample that can be found at Customize the Office Ribbon (It doesn't take rocket science) by Greg Maxey. You can download that template and save it in your Word Startup Folder. XML modification is worth learning but is not nearly as easy as picking things in the Customize the Ribbon dialog.
Here is the same ribbon when Word is in a smaller window;
As you can see, the first group was collapsed to a drop-down and fewer styles are showing.
I created a separate Styles tab using the Customize the Ribbon dialog. I often disable it.
I also have removed a number of groups from the Home tab using the Customize the Ribbon dialog. These changes have remained since I made them. The most recent one I removed was the Assistance group with Copilot and the Editor.
It was arrogant of Adobe to use space on your Home tab. I am unsure how you can deal with that. I have Acrobat but keep it on a separate tab. It may be that it is in Acrobat settings; I do not remember. You may be able to get help for that on the Adobe site.