Oh my man, now this is a thread and then some. Short answer DMC of which it's a much tougher choice I'd have to consider.
I haven't played Bayonetta 3 nor the 2D Ninja gaidens and I failed to complete Ninja Gaiden Sigma 2 but knowing enough about those games to make a decently informed decision I would say DMC, it's the GOAT, it has the gun which a little mechanics goes a long with to adding a faux feeling of complexity and because this is centered on Stylishness it does perhaps not the actions themselves the best but it makes you feel the best about them and getting those extended triple SSSs is like Tony hawks constant combo level of dopamine. It's also something that is easy to learn, Bayonetta is tougher to get a grasp on so you only get into a flow near the end of the game and Ninja Gaiden is so, so difficult and punishing, DMC is just that perfect balance and you can the difficulty settings feel well tuned with perfect incremental ramps. while I think that DMC4, 5 (I also consider DmC a good title, core combat wise) do the heavy lifting for the series as a whole. In fact I've never finished anything in the series before DMC 4 cause I was just not good enough as a youth and they have aged too much for me now. DmC 4 and 5 also have the best level design, maybe 5's astethetic is not as cool but it's definetly better than bayonetta and NG black which are the two that come most to mind. The level of skill you can reqch with 5 also is staggering, like I top out at a certain point and can't get any better but at least I can see other people string together insane combos and make it look effortless. I done some insane shit as Dante for the trophies in 5 I never thought I'd be able to do and DmC at the highest difficulty and some of the challenges you need to complete for the platinum is easily the sweatiest gaming I've ever done, it took me upping my skill level at the game to a degree that I haven't done with a game since, not even Sekiros hardest boss got THAT difficult although Sekiro obviously too longer with wasn't as skill intensive.