> So the word viking, and the period 800 to 1066, show a very limited view of the northern European history.
I'm Danish and I think that it's cool that you like our history, but I would encourage you to be a little more inclusive as far as the word "Viking" goes. As I understand it the word has an origin in what the people around "Viken" called them selves in the period. This is the area around the Oslo fjord and Skagerrak, and it's actually a lot less "sexy" when you know that the word "vig/vik" means "bay". Anyway in Denmark, Norway and Sweden (and possibly more Scandinavian countries) we actually call the period vikingetiden (The Viking Age). I know that a lot of the popular culture (and even academic) focus on the age is on the BERSERKERGANG parts. Probably not too surprising considering ordinary life was really rather mundane, with around 95% of populations in Denmark/Norway/Sweden being regular iron age farmers. I don't think this should discourage you from using the word "viking", however, I don't know any Scandinavians who would think less of you at least.
What we dislike is the cultural appropriation by far right fools. Which has gotten so bad, even here, that I sort of need to wear a giant rainbow hat to signal that I'm "safe" to be around if there is a pride or whatever going on in my town because I look sort of evil to some people. I'd probably describe me as a biker dadbod + beard and tattoos.
> The east coast of England was dotted with roman forts, defended by fast moving Dalmatian cavalry against raids from the north sea. As soon as the romans left we see an invasion of people from Denmark and northern Germany.
This part is especially interesting to me personally. Maybe not so much what happened in England, but the consequences of the Romans leaving France with France subsequently getting rather serious about "being good at civilization". Which meant that they attacked as far as into Danish Sønderjylland, pushing the northern germanic and scandinavian people toward expansion elsewhere. Which is what lead to we now know as the "viking routes"
Anyway, don't let certain representations of "viking culture" (whatever they may be) discourage you from using the word "viking".