The stutter problem does exist for years. I went through with it and found solutions, and it was discussed over and over again. I am kinda tire of it.
DeoVR, if the settings are right, it will playback 8k videos smoothly, but of course it depends on your rig. I used to have nvidia gtx1080 and it was playing just fine.
We don't even know which headset you are using. Windows based or Quest 2 or others.
For Windows, you are using Nvidia or AMD ? Did you try using directshow ?