tbh I think the games work in any order. With how cryptic and fucked up these games are, you can play them in any order and be left wondering what in the goddamn. I played 2 before 1 and played 1 because I wanted to know what in the hell happened before 2.
The only game i would agree on is RRW because its Toros first game and much more experimental in nature.
Blacksouls on the other hand. You can only experience your journey once. The first impact of the twist. The first time you see certain character scenes. Even the first time you go outside the forest sanctuary and either ask yourself is this forest a garbage dump or the dev lazy. The way you consume your media certainly changes your outlook towards it. Of course no one can force you to do anything. So if you play the sequel game first and the original one later its your choice.
But the best experience from my anecdotal pov is you should play BS1 into BS2 like a SEN person would do.
The questions you have inside your mind after finishing BS1 and exploring BS2 or rather being thrown into it are vastly different. If you go into BS2 & then BS1 a lot of the mystery and twist are simply solved already
I dont preach a lot but this is a point i can only say comes from heart. Please dont sabotage your own journey like that.