I’m very late to finding this thread but if you’re recording with OBS as a last resort, I would recommend using 60FPS. Mismatched framerates get less noticeable at higher framerates. I also think you might be able to use mpdecimate to get rid of the duplicate frames, though I haven’t tried it myself.
Also you need a decent GPU/CPU to handle the encoding. Your build not being good enough for high quality recording might be a reason for the choppiness.