Comparing the two non-mainstream releases, Bloodborne got 7.5 million compared to Sekiro's 10. Which actually makes Bloodborne the easy winner because of its single console exclusivity and it being released earlier in From's lifetime (meaning less "will buy every game" fans).

Also any sequel would ruin a lot of what made it good. The lore would need to be raped to keep going, as it always happens to any Lovecraftian story that gets "explained more." And it would be bogged down by all the Current Gen From Soft baggage, much like Armored Core 6 did adding stagger bars, that they seem to be accumulating with each successful game.

Just letting Bloodborne be ported would basically give us a sequel anyway. There is like 10+ unused bosses in the game files that people have found, on top of a bunch of enemies at that. You can access them with the Dev Code Chalice Dungeon, though they are incomplete. But if the game was ported, modders and the like could actually work on and finish those and likely build half a game's worth of not content from it.