I think technological explanations can work. Especially for certain settings.Around 48 percent of the Human Genome contains DNA that is not strictly human and is instead the remnants of ancient viruses. These viruses result in strings of genetic code that move around the genome and paste themselves into different bits, most a benign but when the body is unbalanced they can result in various diseases.
If we look at Vampirism as a sentient magical virus that purposefully transforms a host then the Dhampir works as genetic lineage, the Dwarf host genome has been rewritten by the Vampire genes to create a new genetic line - that can even reproducer by infecting the blood of others.
Even Golems and Warforged work as Lineages if we are happy to accept constructed virus code existing in fantasy worlds (and if you already accept robot people then why not?)
At the same time, I dont want to lose track of "because magic".
Magic has a logic to it all its own, such as function according to archetypes, rules of sympathetic magic, mental intention, and so on.
As long as the technology allows for the magical principles, it is great.
For example, if we look at a vampire, it is a kind of Undead. Actually, it is two kinds of Undead. It is both a ghost and an animated corpse. Indeed, the mind of the ghost is animating the corpse. This ghost has a strong mind, even when death disorients and distorts the desire of this mind to some kind of dying wish.
Essentially, the vampirism has less to do with a virus, and more to do with some specific form of telekinesis.
When a vampire produces a damphir, the mental intention of the vampire results in a transformation of the living body of the damphir.