After recording, you can use a video editor to cut parts of your video file. A simple editor is already on your machine, it comes with Windows 10 and is called "Video-Editor". Search for it on the local machine.
It's also possible to pause a recording in OBS, as long as you don't use the encoder called "(use stream encoder)" for recording. The "Start recording" button is split into 2 buttons if you start a recording, the right half is for pausing.