I just finished the Main Quest now I thought it was much longer and I liked it anyway, I would like some advice I want to play with the current Character Liv.52, with some skills almost 100 (ability to hand I 100), I scream powerful for example, bring a sample of sovngard, I spell "Summon Being Ira" is the skeleton that we are Dawnguard to let you know, I play with only very hard mode with all these powerful screams I am afraid that the DLC Dragonborn is easy to see that I scream loud and strong spells.
So give me advice should I Liv.52 current character or create a new one?

Your post made no sense. Go ahead with your current character. I hear Dragonborn is best for higher leveled characters.

dragonborn is harder than vanilla skyrim imo, also i'm pretty sure a few of the rewards are leveled (miiraak's gear is iirc) so you may wanna be higher leveled to get the best versions of items

Ok, but my only "fear" is that I really do have some good shouts and spells, in that type scream "Champion Sovngarde" (honestly I have not tried) but it seems pretty powerful and so I do not want these screams and powerful spells ruin me the game, ie easily kill the new enemies.

Then don't use those shouts? What the hell is "Champion Sovngarde"? Call of Valor?

Use proper phrases please!