Question / Help Audio stutter when recording 4k 3DS footage


I recently built a workstation PC & have had issues with audio when recording (not streaming) with OBS Studio. I have a Quadro P4000, which is not ideal for recording but I figured it would be good enough for work but also be powerful enough to record solid quality videos.
I own a merki 3DS capture card which runs fine with it's own software:

I've been attempting to record 4k footage from the 3DS, the top screen has a resolution of 400x240 which scales up nicely to 3600x2160.
However, I can't seem to find any settings where I don't run in to any audio issues, or that the quality is not good enough for me.

I have the 3DS software audio running through speakers instead of the montior. It's the only audio device playing via the speakers, so there aren't any random Windows noises or interruptions


Here are a couple of links to videos with the audio jitters:
Various instances with higher quality settings
Lower quality settings (see pics below) - Log file for this vid
I've played around with the video settings the most. I've tried mp4, mkv, both NVENC & x264, CBR, CRF, VBR, CQP & Lossless. I would still get an occassional stutter with CBR with a bitrate of 10 000, which is not the kind of quality I am looking for either




In the 3DS software, I lowered the fps down to 30

I can only change the sample rate of the audio betwen 31 000 & 33 000, I am wondering if this would be an issue as OBS only allows me to choose between 441.khz & 48khz

PC Specs:
CPU: Intel Core i7-9700K
GPU: Nvidia Quadro P4000
RAM: Corsair Vengeance LPX DDR4 2666 C16 2x16GB
Storage: Samsung 970 Evo NVMe PCIe M.2 250GB (C drive), Seagate Expansion Desk 5TB HDD (recording to this drive)
Motherboard: ASRock Z390 Pro 4, Intel Z390

I would like to record the vids in 4k if possible, I thought it would be plausible enough. I don't record in the 3DS' native resolution & then upscale in a video program as the quality is visibly worse
Note that the audio issue persists with lower resolutions. 1080p, 720p & even 800x480 have the same audio stutters - they just don't occur as frequently

Please let me know if I need to add more information, & I look forward to hearing any suggestions
Thanks in advance!