A huge ethnic group?

The Germanic languages (ethnic group) are related in the sense that they can be shown to be different historical developments of a single earlier parent language. Although for some language families there are written records of the parent language (e.g., for the Romance languages, which are variant developments of Latin), in the case of Germanic no written records of the parent language exist. Much of its structure, however, can be deduced by the comparative method of reconstruction (a reconstructed language is called a protolanguage; reconstructed forms are marked with an asterisk). For example, a comparison of Runic -gastiz, Gothic gasts, Old Norse gestr, Old English giest, Old Frisian iest, and Old Saxon and Old High German gast ‘guest’ leads to the reconstruction of Proto-Germanic *ǥastiz. Similarly, a comparison of Runic horna, Gothic haurn, and Old Norse, Old English, Old Frisian, Old Saxon, and Old High German horn ‘horn’ leads scholars to reconstruct the Proto-Germanic form *hornan.

Germanic languages, branch of the Indo-European language family. Scholars often divide the Germanic languages into three groups: West Germanic, including English, German, and Netherlandic (Dutch); North Germanic, including Danish, Swedish, Icelandic, Norwegian, and Faroese; and East Germanic, now extinct, comprising only Gothic and the languages of the Vandals, Burgundians, and a few other tribes...

I have my own personal opinion on this topic. I think the representatives of the above-mentioned nations are distant relatives of each other. This is reflected in their languages ​​and cultures, even in their appearance. I want to know exactly what unites this group. So are they really related? What do you think?