I am not a PC gamer, but I'm debating almost every day with myself if I should get an Xbox One X for DOA6. It's a pretty expensive console and that just for one game (well, the Witcher 3, which is my favorite game this generation, apparently also looks and runs amazing on it.) I wonder if it is really worth it though... Other than some very vague statement that the game will be better looking on PS4 Pro (which I already own) Team Ninja did not make any comments about what kind of upgrades they are planning for PS4 Pro and Xbox One X. If I had to guess I'd guess the Pro version will get a resolution bump up to 1440p, better texture filtering and higher res shadows, and the X might get a resolution bump up to 1880p (I doubt it will be full 4K at 60fps), better texture filtering and higher res shadows. Both will likely have shorter loading times as well, the shortest on the X.
I guess when DOA6Ultimate comes out for PS5 in one year or so, and I will definitely get the PS5 instead of the next Xbox, all my DLC won't be transferable, again. Just like all my Xbox360 DLC for DOA5 wasn't transferable to the PS4 version of DOA5LR. That happening again would suck, lol.