The very best salmon fishing experience with a fly is summer and early autumn coho fishing off the west coast. West coast of Vancouver Island in particular. There are some similar opportunities off the mid-coast and just south of the Alaska panhandle. Some use a fly rod off the northern tip of the Haida Gwaii (formerly Queen Charlotte Islands).
Many BC anglers enjoy chasing pink and coho salmon off the beaches on the relatively protected east coast of Vancouver Island.
All fishing access is governed by rules of unrestricted access and unlimited effort during permitted time and area openings. So in-river salmon fishing in more easily accessible areas can be congested. If you enjoy the sight of anglers occasionally yelling and screaming at each other or getting into a fist fight, or tossing lead weights directly at First Nation drift fishermen, this is could be for you!
Perhaps spending some money on a guide who runs a jet boat would help avoid crowds and help shape a better angling experience. Private message me if you want a recommendation.
Note that the Fraser should ideally have openings for sockeye, chinook and other salmon this summer but could be just as easily be closed.
As a general rule, ocean survival rates of out-migrating fry and smolts have been very poor in the last ~5 years due to warmer than usual Pacific Ocean temperatures. From SE Alaska all the way down to northern California. Planning in advance is tough. A contingency plan or two might be worthwhile.
The Skeena River looks like it will be closed to all angling for salmon this year.
If for whatever reason, salmon fishing does not work out, think about using a 3 or 4 wt fly rod (single or 2-hand) and dry flies for westslope cutthroat trout in the southern end of the East Kootenay District in the southeast corner of British Columbia. There is terrific fishing for westslope cutthroat trout, Rocky mountain whitefish and Bull charr in both the Purcell and Rocky mountain ranges.
It is possible to find East Kootenay water where watching a couple of dozen drift boats and pontoons go by in the morning is standard fare but with some effort, a high clearance vehicle, a solid pair of legs and some map reading skills, you can find stupendously gorgeous water all to yourself. Or hire a guide with a sturdy 4-wheel drive.
Science is not common sense. Much of it is devoted to a systematic documentation of what we do not know and understand.