Protonmail do not have a letter-box presence in CH... They have real employees there. That's quite a misinformed comment. (I said that knowing multiple ex colleague working there in CH).
I also have ex-colleagues working there... in Switzerland.
I was unaware they had any meaningful presence. according to their PR/marketing they do stress since now a few years that they're a globally distributed workforce which happens to be HQ'ed in CH. Looking at their LinkedIn this seems to be correct.