Dark souls 2 and 3 are my least favorites due to not taking the series anywhere new. Bloodborne and Dark souls 1 are on the same level as Demon’s Souls to me, because they all offer relatively fresh ideas. I still think Demon’s Souls has the best boss selection of the series mostly because they are all unique even when their design falls flat they are still memorable.
I make game analyses on youtube:
FFVI: https://www.youtube.com/watch?v=mSO6n8kNCwk
Shadow of the Colossus: https://youtu.be/9kDBFGw6SXQ
Silent Hill 2: https://youtu.be/BwISCik3Njc
BotW: https://youtu.be/4auqRSAWYKU