Wow! You are correct. This surprised even me. Nice find. The steps involving Playlist and Timeline somewhat complicate the story, but it can be used for more advanced scenarios. Many users simply want to do this for a single clip:
- start with no project
- open a clip
- add video filter Crop: Source
- optionally add other filters and trim as needed
- choose Settings > Video Mode > Automatic
- click Export (At this point you can see the Video > Resolution in advanced mode has adopted the new resolution.)
- now you can either export or add this to Playlist or Timeline to start a project
CAUTION: You must ensure the resulting resolution has even values for both width and height for most video codecs to export. It is even possible that some filters will not work correct either.