We're very likely never going to see Bloodborne 2. Notably because aside from the Dark Souls Trilogy, Modern FromSoft seems not particularly interested in doing direct follow ups. Dark Souls was a Spiritual Successor to Demons Souls, Bloodborne was a spiritual successor to Dark Souls. Sekiro took some souls aspects but then something very different with it in its combat system. Elden Ring is basically a big spiritual successor to all the games they've made in the last 15 years without being a direct follow up.Dark Soul 2 was trying to be something notably different from Dark Souls but the troubled dev cycle and console limitations ended up causing it to be something quite different then it's original intent. Dark Souls 3....feels almost like a apology for Dark Souls 2's reception, considering how was mostly a refinement of Dark Souls and Bloodborne and mostly ignored 2 entirely.
Also the fact that both Dark Souls 3 and Elden Ring show obvious influences from Bloodborne, both in Some of the level design(the Eternal Cities in feel like something directly out of Bloodborne) and the emphasis of horrifying things filtering down from the stars in Elden RIng. Dark Souls 3, aside from the faster combat system, has a big theme of humans reverting to beasts.They're already cribbing elements for their other games, so it feel less likely they'd just do a flat out sequel when they can just crib themes and iconography as needed.
But honestly the big thing is the fact that Bloodborne 2 would have surpass the expectations of the original game and I have no fucking clue how they would do that at this point. Bloodborne feels like lightning in a fucking bottle and while it's not perfect, it's so tight and finely tuned that it made a great impression, but trying to just do BB again would be underwhelming at this point.