Beat (not completed) the Vampire Survivors Castlevania DLC, it was absolutely worth it. My initial annoyance at having to unlock practically all the characters just to get Richter was gone by the time I could play as him. There's so much love for Castlevania as a series of games poured into this DLC. Definitely going to be spending some more time playing in the near future.
Sadly (or maybe thankfully) Konami likely doesn't see the same value in Castlevania, a cult following decent amount of people who adore the series simply isn't the same as the mindless mass of consumers they want to sell their games to (Dominus Collection is estimated by steamDB to have only sold 120k over the past few months, while Advance collection has its highest estimation around 275k over 3 years, nowhere near what Konami would like). They could at least offer the license to people who do care beyond making DLC, but that's very unlikely and could easily lead to its own sort of bad games.