Grasulf Ier de Frioul, Duc de Frioul, - Real or Fictional?

I was tracing a line using this site:

https://gw.geneanet.org/foullon?lang=en&pz=matheline+marie+herm...

but when I did a search on Geni for this Grasulf, I found this profile that states:

This tree has been isolated from other trees on Geni: Tree contains duplicates that should be deleted. Why would they be deleted instead of merged?

Then I also found these two that says the lines are fictional:

Grasulf II De Frioul

Grasulf I De Frioul

both of the two above Grasulf I and II show wife as Romilde.

I have no idea if the people are real or fictional, if they need merging or deleting.

Thanks in advance for any clarification / assistance.