Not really that simple. Rocky is direct 1:1 with RHEL, so if RHEL don’t provide it then Rocky doesn’t have it either. The problem is, and you’ll find this with a lot of other projects like ddwrt or openwrt as well - a lot of them are not providing support where broadcom stuff is closed-source and difficult to get working. Sometimes on the ddwrt or openwrt projects, the devs will try to get something working if someone donates routers to them to use for developing and getting drivers working. Therefore, unless a Rocky Dev or any other Dev has the same device/hardware as you to be able to find a way forward to make their own driver and provided it, then it’s unlikely to be done.
If you haven’t tried already, take a look at ELREPO or RPMFUSION in case any of those repositories has a kernel module for your particular card. Or perhaps even kernel-ml or kernel-lt from elrepo instead of the 5.x kernel with Rocky since both of those are 6.x kernels and may have the support you need to get it working.
Also, according to pkgs.org - https://pkgs.org/search/?q=broadcom-wl there is broadcom-wl package in EPEL.