Not really true. The difficulty is Prince V is a very self contained package of PUNCH HARD so can slot into virtually any type of list. You’ll probably want something else durable and fighty to take advantage of Prince V Command ability; ideally something that can in return offer V something back like increased survivability (Neferetta) or optimising damage output (Radukar the Beast, Mannfred, Nagash if your crazy) or a utility piece for a artefact/traits (Vengorian Lord, VLoZD).
After this you probably want some mobile Lane blockers like Dire Wolves, Fell Bats or even at a push Black Knights to help prevent PV getting bogged down in the wrong fights.
Then you look to shore up the weaknesses of the list; Claiming and protecting objectives, grinding fights and shooting. So either big or tough units and this is where Soulblight opens up as there are just so many options. Zombies, Skeletons, Grave Guard, Blood Knights.. All with a slightly different role and focus.
Prince V naturally lends himself to being played in the Kastelai dynasty as they’ll get to benefit from all the traits and artefacts. But again their self contained nature let’s you drop it into other dynasties without major issues.
If I was buying my way into Soulblight I’d grab the Flesh Eater Courts start collecting for Prince V (and some Vargheists) (flip the ghouls If you can), Start collecting Soulblight (20 Graveguard are great) and then a box of Dire Wolves. Better to start small and build out.