But even if you consider them non-Germanic, they were ruled by the Norman nobility and still ruled by them de jure via the Royalty

The best way to understand the history and culture of the UK is to look into the normans.

IMHO the problem with Germanics is that they are constantly assuming good faith on their opponents and they've also spread themselves too thin. There are german all over the western world. Part of the reason the core continental germanic reich lost WWII is they were fighting germanic soldiers from the americas and germanic soldiers living in russia. It's more about the displacement of the race. We will have a germanic imperlialism once we rediscover our roots. No more brother and cousin wars.