Is your feature request related to a problem? Please describe.
/fill could do the same as /setblock but with two sets of coordiantes. Or, you could get bits that are the same pasted with one command.

Describe the solution you'd like
An option in the config menu to use /fill instead of /setblock

Describe alternatives you've considered
I have considered WorldEdit, but that will need to be on the server and I want client-side things.

Thank you for reading my suggestion.
I hope that it will get implemented.
👋

This is planned, but sub-dividing the schematic to somewhat optimal fill regions is... not super trivial, and will need some head scratching. And also this is not really on the top of the todo list atm, there are several other bigger/more common issues and needed improvements and missing features etc.

Thanks.
I look forward to seeing it added.