???
I livestream and record a regular house of worship service. I'm recording/saving to the local C:\ users directory, which happens to be a NVMe SSD. When I hit stop streaming/recording when I'm done, I have OBS settings configured to auto-remux from MKV to MP4 and that takes about 20 seconds to write a copy of the 10GB+ file (1080p 30fps 1hr plus) and then I have both the MKV and MP4 file. That extra 20 seconds isn't necessary as I originally started simply saving the MKV and that file is done/ready essentially immediately upon ending recording (faster than I can ALT-TAB to file directory and do anything with the file, so close enough)
so I'm not sure what your looking for?
The point of OBS is real-time video compositing (which entails encoding) and is VERY computationally demanding. The same is true for video editing, and any real-time encoding application. Modern phones, tablets, cameras etc have dedicated chips to do the encoding, with limited options/flexibility. OBS and similar have LOTS of flexibility and options. If someone doesn't know what they are doing, or aren't careful and understanding settings and their implications with OBS (or similar), a person can easily overwhelm even a $5->10K workstation PC
SO, I'm not sure what you are doing that is, by impression, taking an extra 2 hours? maybe you are remuxing but writing to a slow HDD which has something slowing it down, like security s/w or ??? or worse, writing the remux file to a slow USB external flash drive??
And Export has a specific technical meaning in an app like OBS, ex an export of settings, etc makes sense.
Exporting video does NOT make sense, as OBS is not a video Editor. When one finishes recording in OBS, the video is done and ready (or should be unless specific OBS setting to the contrary .. ex remuxing), or a computer (not OBS) has a problem
So maybe clarifying what you are asking for/about?