Not sure my exact playtime at the moment because it's split between PS4 and PS5 but I can tell you I spend 30+ hours per level. I try really hard to figure things out on my own so all the trial and error really adds up.
Yeah spending that long on each level would add up fast, I normally go in guns blazing learn the layout and locations of people. Then try and do it Silent Assassin after
Across the three WoA games I've clocked about 320 hours, and then probably about 50 in Blood Money, though that's a lot harder to gauge since I beat it when I didn't have it on Steam, then got it on steam and put another ten hours in, so 50's just a guess
I think it'll be harder to go back to those with how polished and modern an experience WoA is, but Blood Money still does some cool things. You might wanna check out the Blood Money Reprisal version they put out recently, it adds a minimap, instinct mode, and some other mechanics from WoA to Blood Money in an effort to make it more approachable