According to this Reddit, yes:
As long as the region matches, the save data should work.
Users can confirm this works with games like Battlefield 4 and Horizon Zero Dawn, so it should be the same with your Dead by Daylight.
Also, for your second question:
To make sure the game saves carries over, I copied the save file to a USB to be safe, deleted the application game data, then downloaded the digital version. Started it up, and acted just like the install from the disc. Didn’t even need the USB.
Edit: @childe, wondering about Behaviour account, I found this Reddit:
DLCs and cosmetics are bound to your account and are digital so they should be fine, as for data it should not matter what copy do you have
and this one:
Of course you'd keep your s**t it's tied to your PSN not your game copy.
Play the digital one and all save files an accounts are there. User Game data and save files are separate from the actual game files.