"forever" is maybe not so nice but I agree that changing many processes via the user interface is not ideal. We use Python and SQL typically for that.
The import of Excel dataset works (so, "Why importing processes from Excel does not work?") is not correct:
Import process into empty database
Process in the previously empty database.
However, if you make a copy of the excel file and only change some numbers and text, e.g., then it will not be recognised as a new dataset, since the process is recognised by its UUID, and an overwrite or entering a copy of existing elements is only possible with JSON-LD files.
If you enter a different UUID in the excel however, then it will be recognised as a different process dataset, and can be imported (the yellow colour is not needed of course).
(and it is good to also change the name which I didn't do now).