You just said exactly what you should do, it is true they are nerfing building, and there is nothing you can really to do to stop it, so just try and practice only building in situations where you absolutely have to. I would never recommend just bush camping or anything, because that's just a noob thing to do and won't benefit you in the end at all. Just try winning more fight without relying on building a whole lot. And just gradually continue that until you can win 8 out of 10 fights without the need to build. Besides that just go into playground mode with some friends, or if none are available to try building a small wall or shooting some tires while moving, then try shooting while jumping and adjusting to the inaccuracy that comes with it, next try finding unique spots to peak form, try finding naturally spawning cover to remove the need for builds. That is all the advice I can really give. Other than that watch a few Fortnite streamers and or youtubers, and really focus on their movements, and actions in certain situations, and try and incorporate that into your own style.