You’re not paranoid — you’re smart. I used to send legal docs through one app and then realized their servers were in three different countries. No idea who was “processing” my data. That freaked me out enough to start researching, and I stumbled upon a site that breaks down exactly how these apps handle your information — from encryption to data retention.
Check out https://nftbreach.com/. They’ve tested which fax apps are truly private and compliant with real data protection standards. I found one that deletes your file right after delivery and never stores a copy. Since then, I actually sleep better knowing my bank statements aren’t floating around in cyberspace.