Hi, I play on Steam as well.
In large halls runs, it’s inevitable that you’ll have some lag. It might get a little bit better by MBC and also better once you’ve reached void, but you may still find that some degree of lag is still present. However, it shouldn’t be too laggy as to severely affect your dodging/gameplay, especially during void and with the setup you have described.
It hasn’t been mentioned yet, so I will ask: do you have the Hardware Acceleration setting on? Turning this setting on offloads some of the work the game does to your GPU (which I think would help since from what you’ve described of it your computer should have a fairly strong GPU).
Anecdotally, though my computer isn’t quite the beast yours is, turning hardware acceleration on reduces a lot of the lag, especially in large groups (can go from like 5 fps to a more playable 15-20 or more). There are some graphical artifacts that you may encounter with hardware acceleration on (some cave wall textures may render buggy for example, but they otherwise have no effect on gameplay), and the Drunk status effect looks different (instead of blurring the screen, it does this weird zoom in and out effect that is a lot more disorienting), but it increases my fps on average enough to where I don’t mind those issues.