Thank you. I ended up doing something similar, but simpler for me to setup.
I made a clean version that had the correct result in the early part of the video, but erroneously deleted desired objects in later parts of the video.
I then loaded the clean video into a higher track, and deleted all but the desired clean portion.
That way the clean portion overrides the original only in the time frame I wanted.
I find cutting, positioning and transitioning video clips next to each other on the same track to be more complicated and error prone than having two identical length tracks aligned at the beginning, and then deleting the undesired portion of the higher level track. There is no need for transitioning because the frames in the lower track align perfectly with the frames in the upper track. And there is no risk of unintended fragments when I can't get the clip insertions perfect.
It would be nice (at least for me as the user) to be able to specify the both the track and the start and end times to which an effect is applied. That would both shorten the processing time and prevent unintended/undesired results.