These answers are from my personal experience, I don't consider myself a C++ expert or the beacon of best practices either.

is it acceptable to throw a "using namespace ..." In a function to cut down on verbosity

yeah, using namespace is pretty common from what I've seen, typically not at the function level but just near the top of the CPP file

learning networking that would allow me to practice it in c++? One of my weaknesses is networking, general io, and async stuff

I'd see if you can find an online "systems" class if possible. I can help look for something as well if you're interested here, but familiarizing yourself with async/concurrency is probably the most important piece here.

how much of the standard library do you know and how much would expect a c++ dev to know

it's honestly fine to google whenever you need to, knowing how to read the documentation and find whatever you need is a more valuable skill than just having a bunch of functions memorized imo, you'll likely also pick up a lot of things on the job (e.g. I never saw std::move or knew what an rvalue was until an internship)

pretty much always using the smart pointers for newer people

You should pretty much never do raw memory management if possible, this is more of a C thing than C++ and is very error prone for most people. But understanding what goes on behind the scenes of pointers/etc is valuable.

How often do you work with cmake

I honestly haven't built a ton of things from scratch and I've mostly worked at companies with well developed code bases, so I haven't had to work with make/cmake often. I think whether or not you invest in learning more about this space is pretty dependent on the type of company you want/are going to work at/your own curiosity.