There are quite a few threads on cameras already here. Lots of different options of course. The two I see the most are the marine-grade cameras provided by the big manufacturers like Raymarine, which will integrate pretty easily with MFDs and such, and much cheaper solutions using security cameras, etc.
I chose sort of a hybrid of the two and bought an AXIS camera server that works with my Furuno stuff, and then security cameras from a big vendor that are stainless steel and water proof.
Like you, I can see astern and forward very well from my upper helm, but I can't see the dock edge as well as I would like. I added a camera in the engine intake area that points at the dock edge, and not only shows me the dock, but the rub rail on the boat, and the person stepping off the stern.
It has been a lifesaver in terms of getting the boat right up to the dock safely. Here's the model I bought for outdoors
. I bought some cheaper ones for inside. It runs off of 12V (I used a stable converter supply) and has a lot of mounting choices.