Well, I suspect you could edit a video in that way using OBS... you just don't want to... as OBS is totally wrong tool for the job.
By rendering then re-encoding there would be a generational loss in image and audio quality, etc (think old school making copy of VHS tape)
so you could play video, mute at appropriate time, and use mic to input new audio... but the results likely wouldn't be what you are looking for...
Koala's suggestion is a MUCH better idea, less frustrating, better results, etc