I don't know much about pc's but theres a possibility of some type of bottleneck. before i upgraded my cpu it always ran at near 100% in fortnite and now it rarely goes above 60%. In my case I think it was because my gpu was far better than my old cpu and it couldnt keep up. I have an rx 5700 xt. My old gpu was a r5 3400g and now I have a r9 5900x.
#100 percent cpu usage on Fortnite
distant wadi
wet aurora
Lots of the benchmarks i'm seeing also commonly hit in the 90-100 range on cpu, also keep in mind that most people that do benchmark vids like this will be using a fresh install of windows with very little background processes
tldr is get a better cpu to get rid of the bottleneck, that'll likely end up requiring an upgrade of both cpu and motherboard though