North-facing spots in West Seattle – especially higher-up – have a good view of the Lake Union fireworks. Three Tree Point is nice but I to date haven’t found a viewpoint beyond standing on the side of the road in Arbor Heights. Since, even pre-WSB, I almost always had to work the 4th, we went a couple years to the Poulsbo 3rd of July show. Also, depending on where you go, there are spots in WS where you can glimpse the Vashon or Bainbridge fireworks … Also, not too far south, Des Moines has a show:
https://www.destinationdesmoines.org/fireworks-over-des-moines