You could whip up a quick script to move driver kexts for mic and camera in and out of extensions folder essentially toggling the functionality. This would require a reboot though.
I put an inline switch on the supply line of my thinkpad camera. The hardest part is mechanically placing the switch so it's not in the way and can be used easily.
It's actually getting worse. The 2020 macbook air has soldered secondary storage. In a day when NVME drives are as tiny as ever. So now if you want to upgrade from 256 GB to 1 TB you need to buy an entirely new board.
I'm not sure, but hasn't it been like this since... 2018 or so? I thought all after-market upgrade possibilites were gone, because they started soldering the RAM and everthing else. Didn't knew you could upgrade any storage at all.