Honestly, B650 is more than enough for the 7800X3D. The CPU is incredibly power efficient, drawing around 80W max during gaming, so you dont need the beefier VRMs or extra PCIe lanes of X670 unless you have specific storage setups. For your budget and specs, I went with the MSI MAG B650 Tomahawk WiFi for my own build and it has been rock solid. Here is how it lines up with your checklist:

• It has exactly 3 M.2 slots (two PCIe 4.0 x4 and one PCIe 3.0 x4).
• The audio codec is the Realtek ALC4080, which is way better for analog headphones than the basic ALC897 on cheaper boards.
• Boot times are decent now after the recent AGESA BIOS updates, sitting around 15-20 seconds with Memory Context Restore enabled.
• Wi-Fi 6E and Bluetooth are built-in. Another option is the ASUS ROG Strix B650-F Gaming WiFi if you find it on sale, but the MSI is usually cheaper and has better VRM temps for the price. I would avoid the Gigabyte ones if you want to dodge coil whine, their QC has been pretty annoying lately.

Just catching up on this thread and had to chime in! I actually built two systems with the 7800X3D last month. For my brother, I risked it and went with the Gigabyte B650 Aorus Elite AX V2. Honestly, the internet drama is overblown. After a quick BIOS update, his boot times are blazing fast and there is absolutely zero coil whine! It is a fantastic budget option. For my own rig, I grabbed the ASRock B650 Steel Legend WiFi. I love it! The board is a total beast. The PCIe 5.0 support is amazing for future-proofing, and the analog audio output is crystal clear on my studio headphones. Plus, it easily fits three M.2 drives. Definitely stick to B650 and save that cash for a beefier GPU!

Dude you are gonna love the 7800X3D! It is legit the best gaming chip on the planet right now, totally amazing choice. Honestly, ignore the X670 hype unless you need like a billion USB ports lol. For your budget and that audio requirement, you should definitely check out the ASUS ROG Strix B650-A Gaming WiFi. It uses the ALC4080 codec which is way better for analog headphones than the basic stuff on cheaper boards. Plus it looks fantastic in a build! If you want the fastest boot times tho, ASRock is absolutely killing it lately. Take a look at the ASRock B650E PG Riptide WiFi. It gives you PCIe 5.0 for your GPU and main SSD which is sweet for future-proofing, and it easily fits 3 M.2 slots like you wanted. Ive built with this one twice recently and the bios is super snappy. You really cant go wrong with either of these!