private from whom

large companies, that should work

the state if it does an criminal investigation, that won't work, also at least for now there is no need to do so if you don't to anything criminal. Sure if fascists take over that would change but they then also would ban any system which would allow avoiding their gaze so not sure it's relevant tbh.

and as things are currently you have to far more worry about US companies and state knowing about what transactions which are legal but you want to keep private then about your local EU government