Welcome to the forum!
I have an 8' Cortland 5/6 weight that I've been using for over 15 years as my pond/lake rod and I love it. I don't know how much it cost, but it casts amazingly well in all conditions.
Maybe I'm an awful fly fisherman, but I never clean my freshwater lines. The one that I use for ponds/lakes is over 15 years old and has never been cleaned, but it doesn't have any dirt built up on it and it casts fine.
As for flies, my favorite panfish fly is a hornberg streamer. Panfish in general though like anything bright, so I'll use a Royal pattern of some sort a lot with a good amount of red on it. Bead head crystal buggers are another great panfish fly. I like to use Dahlberg diver style flies for bass around me since lakes tend to be weedy and sinking flies just get hung up a lot. I find some of the smaller striped bass saltwater baitfish patterns work very well for largemouth too, and you can also try a woolly bugger or crayfish. One of my other favorites is a yellow marabou streamer about 2.5-3" long with a 1/2" thread head on a size 2 hook.