From time to time we can have issues with colors after recording session in OBS. Colors are pale, washed out almost colorless. You can try to tweak those this way:
In OBS go to Settings > Advanced > YUV Color Range and switch it.
Im using Color Format: NV12, YUV Color Space: 601, YUV Color Range: Partial and it made huge difference for my setup. Others use Full.
If you using NVIDIA drivers there is also one more trick ti fix it. Go to NVIDIA Control Panel > Video > Adjust Video Color Settings > With the NVIDIA Settings > Advanced > Dynamic Range: Full (0-255).
I tried to tweak those and reboot OBS or even PC to be sure that new settings are used. It is a hit or miss but once you happy with results you don’t have to touch this setting ever again.
The best way to check it is to put static image in OBS Scene with Black and Colors and compare the recording in high bitrates to original image.