I know that a lot of people have been talking about having a code in a physical sourcebook to then redeem it on DDB. I know that having a code in a physical book would not work very well but what about having the option to get a physical copy of the sourcebook when you buy it on DDB.

That gets floated a lot.  Basically, WotC/Hasbro with one exception (Hasbro's sort of in house Kickstarter whose name escapes me at the moment) doesn't do direct sales of its physical product.  Books and toys are manufactured overseas and put into a vast distribution network it doesn't really control.  

A lot of smaller press TTRPG publishers do direct sales and often bundles those sales with a free pdf (heck some will send you the PDF if you show them a picture of the product in your physical possession and some form of receipt.  Hasbro/WotC just work at a scale entirely different, where they defer to online and physically retailers more set up to deal with the volume.  

I just don't see anything new coming under this sun till there's a new line of core products presumably in 2024.