Offers a Free MP4 Trimmer where you can upload your file and use handlebars to select the exact "piece" you want to keep.

How to split or cut videos and audio assets - Microsoft Support

For a built-in option, open your video in the Windows Photos or Clipchamp app, move the seeker to your desired point, and use the Split (scissors icon) or Trim tool.

Provides an Online Video Splitter that allows you to upload an MP4, cut it into multiple parts, and export just the segments you need.