Info:

OS Name    Microsoft Windows 11 Pro
Version    10.0.26100 Build 26100
Inkscape-1.4.2_2025-05-13_f4327f4-x64 (fresh install 7/3/2025)

1. New Document
2. Insert two flowchart symbols
3. Select both symbols
4. Unlink Clone (no idea what this is doing but nothing works if I don't)
5. With both still selected Align on horizontal centers
6. Unselect both
7. Select Connector Tool
8. Click on center "handle" of first symbol
9. Click on center "handle" of second symbol
10. A thin line will appear between the nearest points of the two symbols (and it will be selected)
11. open Fill and Stroke panel
12. increase "width"
13. The "bounding box" (only description I can think of) will expand as the width value is increased but the line will remain the same thin thickness.

This is not desired. I expected (like on all the YouTube videos I watched) the line to increase in width.

Maybe this:

Well that was easy for YOU to say! Why wouldn’t “normal” be the default?
 

now with display mode “normal” when I type text it comes out unrecognizable. Switching to “outline” I can see the text fine.

Never mind. I had “Stroke paint” set to flat color. No idea what any of that means but clearly you don’t want that when you are adding text!

This is going to be a painful learning curve. I’m new to this software and new to vector graphics in general. 

The tutorials in Inkscape's Help menu are fast, easy and get you pointed in the right direction.