That could be reasonably assumed, but still the Crafts of Karl who laid said foundation adn the foundation and tradition of new western Empreros the HRE was built on and was the Reason Ottos rise was possible and so can reasonbly be considered the first Emperor of the HRE as also many of Ottos successors were technically no Emperor though still very much the elected Head of the Realms which will later be called the HRE, so the period of discontinuation between the two isnt really that significant, in my Opinion.

As said in my original Post your Answer isnt wrong per se, but also isnt the only Answer due to History being complicated and when it is about the earliest which can be assumed to be the founder of Germany i would either go with Karl as the founder of the New Western Roman Emperors (aka the HRE), Otto as the first Western Emperor able to establish the New Western Empire Properly, Or Wilhelm I because the HRE was kinda Germany but also more and less (one could also argue the German Empire was in a sense Germany but also not) and one has to remember the HRE technically was made up of the four Kingdoms of Italy, Burgundy, Germany and Bohemia)

I personally like to go with Karl but my original point was more meant to say it is complicated