Big Sur 11.0.1 mostly working on 6700K Z170n-WiFi RX580 OC 0.6.3

CPU: i7-6700KGPU: RX580RAM: 32 GB 3200 MHz CorsaMotherboard/Laptop Make and Model: GA Z170n-WiFi ITXAudio Codec: ALC1150Ethernet Card: Intel I219Wifi/BT Card: Broadcom 4352Touchpad and touch display devices: N/ABIOS revision:Which of the guides on the sidebar you used. Dortania OC

What's working:

• Wake from Sleep (Sort of. It takes a few seconds)
• Ethernet
• Bluetooth (Weird, since WiFi isn't and they're on the same card.)
• iServices (As far as I can tell, it's all working.)

What's not working:

• Wifi (It's working fine in Catalina with the same EFI) -- I added brcmfx-driver=2 to my boot arguments to no avail. It's strange because Bluetooth seems to be working fine. I assume that my Broadcom BCM4352 is just no longer compatible. Is there something newer that's compatible with my MB?
• On-board audio (Also working fine in Catalina) -- The audio layout is different somehow. In Catalina, the rear and front audio ports were listed as "Line Out". In Big Sur, it's somehow switched to "Internal Speakers". That's not the biggest deal, but it's certainly weird. I've also tried alcid=2 and =11. I'll eventually go through the remaining layouts, but since rebooting takes about 10 minutes, it might take me a while.
  
• Sidecar (really, I just don't have a current iPad I can use to test it).
• Airdrop

The biggest issue I'm seeing is that booting into Big Sur takes FOREVER!!! Catalina takes 18 seconds while Big Sur takes 4 minutes and 15 seconds. It seems to be getting stuck at:

https://preview.redd.it/35zog3d4pjz51.png?width=4032&format=png&auto=webp&s=817f1a925cb6313b5b043458915264c584cbcb38

It boots eventually, but 4+ minutes is a ridiculously long time.

Any ideas?