HarrietTheSpy
I understand the trepidation, given the (correct) warnings usually issued about messing with it. But honestly, this registry hack is easy (if you are not in an enterprise environment) and, relatively speaking, safe.
But given your starting "braveness" level, why not just have a look in your registry for starters. You can't do any damage by looking at it. ... Unless you inadvertently try to delete something or add something and accept the change! But you're always presented with the option of keeping the change or not.
Run the registry app (use Windows search). What you see will be a little like any file explorer, fundamentally (it's just a database). Then just drill down and have a look to see whether you have the following paths:
"\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\ExperimentConfigs\Ecs\word"
and
"\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\ExperimentConfigs\FirstSession\word"
You just expand "\HKEY_CURRENT_USER", then expand "SOFTWARE", etc. When you get to "word" in both instances you have a choice as to whether delete or back out by closing the Registry app.
"Hack or Modern Comments? Hack or Modern Comments? ... Which do I prefer?" 🙂
If you have those paths, just hit your keyboard Delete key or right click and choose delete. You are prompted as to whether you want to delete. You can always choose "No" at that point.
You will need to do those ops before opening Word.
If those paths are there then the *.reg file I posted will work (unless you still happen to be running W98 or NT 4) and you won't have to go the manual deletion route.