Mostly, the engine upgrade will just let us work more efficiently. I'm not sure what your knowledge is on game dev stuff, so apologies if this is a bit basic:
An engine is pretty much like a tool belt for making games. You've got your hammer, saw, screwdriver etc. but just having those tools doesn't make anything, they're just tools. We use those tools to make Mordhau, and with the engine update we're now getting more tools that are more useful. The engine update doesn't exactly = more stuff, but what it does mean is that we will have more options and more efficient development going forwards.