Many users are modding the card and re-routing USB to a USB 3.0 card or USB 2.0 Hub. The culprit for my BCM 20702B0 card not working after Monterey Beta 1 is USB. This weekend I started experimenting with a Lenovo WiFi 802.11ac/Bluetooth 4.2LE PCIe card using a combination of Open Source drivers that mess well with Apple's and was able to get Handoff working with Monterey Beta 2 and currently have WiFi and BT working on Big Sir 11.2.3 and Monterey Beta 2 and 3.
🍔 Big Mac 2 For Mac enthusiasts who want to run macOS Big Sur or macOS Monterey on Unsupported Mac hardware.