What's up with WiFi/BT module replacement in CNVi motherboards?

I've seen lots of people claiming that even though their motherboard had an Intel AX210/211, they were able to buy M2 Broadcom modules from AliExpress and replace it, which will then allow them to unlock all of the native macOS features of that module (such as AirDrop). The thing is that, some others, say that their motherboards are just CNVi “locked”, and they actually have to either use a M2 NVME adapter to put the module through, or use PCIe boards. How exactly do I find out if my CNVi motherboard is “locked” or “unlocked” to do this kind of stuff?