Broadcom wifi cards are a nightmare on any flavour of Linux due to the closed source drivers - ie until they are hacked by the clever kids the rest of us are stuck.
You MAY get it to work with the "kmod-wl" pkg from the rpmfusion repos.
Install the repos from here: https://rpmfusion.org/Configuration/
Then update your system as usual (sudo dnf update). If you get a new kernel then reboot your machine before you proceed.
You can then install kmod-wl, reboot again and then try to connect
# dnf install kmod-wl
Your mileage may vary.
If you get no luck your only other realistic option is to buy an Intel based card (or Realtek at a push).