Yeah, Intel AX201 WiFi 6/Bluetooth 5.0 IIRC. The issue with rewriting both the CMOS and EFI sections is the signing needed for them to show as valid. MS assigns those to tested loads so it's very unlikely that a bad guy will get it right. The work around for that is for the bad guy to disable that functionality in their version and basically replace everything with the custom version. Needless to say a lot of that requires knowledge of the hardware involved, so a version for each model type. It's always possible that someone could do that, ut as I was saying before it's very unlikely for someone to do it unless there's a big potential for gain at the other end. Malware isn't typically created just to see it spread, it's created in order to bring some type of gain for the creator. That might be access to private data for resale, such as credit card info and passwords, access to the hardware in order to form a portion of a botnet, so they can extort funds from website owners, or encryption of data to extort fund from the machine owner. Each of those require some threshold of potential return on investment to offset the effort used in creating the malware package. For something as targeted and detailed as you are describing there would have to be a significant return... Now you might have a large enough net worth or have access to sensitive enough data, but if so you'd be more likely to junk this system and get a new one than to be trying to fix it yourself. I think it much more likely to have been infected with a typical key logger/remote access malware package in the OS than a BIOS attack.

Which antivirus are you running? Have you tried running a scan with an alternate such as Malwarebytes?