I was so excited because the program finally opened, but now of course, my tablet isn't working well with it. I get lag and straight lines darting off my strokes.

Well, there's progress at least!

Krita on macOS doesn't have its own tablet code, thats all handled by the OS... Which tablet do you have? Huion is known to give problems. On windows, straight lines at the start of strokes have to do with the double-click settings in the wacom driver. Do you have pressure sensitivity? You can also experiment with the display settings, if your mac only has an AMD GPU you might have to disable canvas accelration. If it has an integrated and a discrete GPU, you might want to use the latest nightly which makes Krita run on the integrated GPU.

I took a break I suppose out of frustration, I have a Huion H610PRO 2048, what's odd is I can zoom in and it'll render okay, but zoomed out on a 2700x3600px canvas it just lags and shoots off straight lines. I messed with the display, the stabilizer, all that and it's not done anything. I have pressure sensitivity, and it works in every other program. I have the most recent tablet driver, now the most recent Krita release, and it's just dragging through hell.

I have a Huion H610 and I get the same problems in Corel Painter as in Krita with macOS. Until I tested with Corel Painter I was prepared to believe that it could be a problem in the way Qt uses the native macOS tablet api's, but I don't believe that anymore.

Hm. I suppose I'll just have to invest is a different tablet for this program at some point. The driver for this tablet hasn't been updated since 2017, and when I ask Huion's support they just point in this direction.