You can force it to do that if you really want to, but by default it will speed it up to 24.00fps and play it alternating between 2 and 3 screen refreshes for each frame (i.e. 3:2 pulldown without the interlacing).
Is there any way to make it work with adaptive refresh to play the video at exactly its native speed and adjust the display refresh rate instead? Or should that just work automatically?
VRR support for MPV is disabled by default in /usr/share/drirc.d/00-mesa-defaults.conf. I am not sure why, because it works for me if enabled. Just fullscreen MPV and it will change the display refresh rate. This requires VRR enabled in both Xorg and your monitor's settings. I have not tried this with Wayland.
