It would be easy to do this for existing notes. You just need a way of programmatically creating the file name for the note, and then you’d just tell the Obsidian URL scheme to open that file.
The following shortcut should be easily modified to do this:
https://www.icloud.com/shortcuts/8b3b1bbf7f3d42e6996fd04c4403a2f9
I don’t know exactly what kind of string you need to provide in order to get it to fit with the name of your weekly note, but it should be possible. Share an example weekly note name and I can think about it, if you can’t figure it out yourself.
Getting a shortcut to create the weekly note if it doesn’t already exist it’s also possible, but it would be much more involved. You would need to have someway of detecting my data file already exists, and then if it doesn’t, you would need to invoke some kind of macro — or embed the template for the weekly note directly in Shortcuts — in order to create it properly.