@TW42 There is a javascript written by a user that does what you want. It requires the use of tampermonkey and the installation of the script.
here is a link to the page with the information. or if you want, just do a search on "set canvas default due times"
set canvas default due time
Unfortunately, I just tried it out (I had it turned off because I did not need it), and it seems to no longer work. I know Canvas has been modifying parts of the underlying aspects of the display information. So, they changed something that broke this script. Unfortunately, I do not know how to determine what.
If you want, you can try it and see if it works. It was working in early 2025 as I was trying to put the same option in for the until times and did not have any success modifying the script.
Ron