In my mind, no. The reason is both these myths and the mixing up of them came by fiction writers after the original stories become old history.
The original Vlad Drakul the Impaler was not an energy vampire, he was a heroic warlord defending his country from a Turkish invasion. The vampire part was invented by Bram Stoker and inspired by stories of Revenants form the same region, but they’re not related except in western fiction. Vlad Drakul was not a Revenant.
Dragons are not typically seen as vampires - dragons have varies myths ranging from being extinct animals to representations of everything humans fear, to conduits for energy.
The Draconian Current of magick, a la folks like Asenath Mason, view some spirits as dragons. I think some are seen as vampiric like Lilith sometimes, but I see then as higher beings that have no need for human energy, being a) not Earthbound and b) having their own energy sources (like, humans eat food and breathe, they have their own ways)
I’m not sure, but I think I recall Blackwood claimed there’s an order he got his info from and he has made this connection of the word “Drakul” to his work. I don’t believe a word of it because as an energy worker I can see the holes in the premise, and this the whole human vampire thing is mostly ill-advised if not harmful nonsense. My personal stance on that where I explain myself is here. Probably not a popular opinion among the terminally edgy but I’m all about practicality not looking pretty.