You can directly edit the downloaded code when using modules, you don’t need your go.work flow at all. I often do it while debugging particularly weird bugs or to better understand library code I’m using.
You can just edit the copy that ‘go get / go build’ download to your system. Afterwards undo the edits or re-download the module to wipe out your edits. No need to use go.work, local replaces, or anything. The files are on your disk!