I tested it on Brave mobile (Android) and I got different fingerprint each time

Can this software be deployed locally? I wouldn't feel comfortable with putting all my contacts in cloud

It's open source and the readme offers (very basic) instructions on how to do this.

plot twist: it also runs rootkit

Have you ever heard about OpenEHR? https://www.openehr.org/

FWIW, pretty sure duffpkg was involved in the creation of OpenEHR, and therefore probably has heard of it.

but doesn't it solve problems he wrote about (Epic and vendor locking of data?)

Conceptually, yes, it solves a small corner of them.

I'm going to ballpark migrating from Epic to OpenEHR without losing data would probably cost you something around $500/patient. So consider a medium-sized hospital that has 250k patient records. $12.5m project. That takes 2 years. (I'm considering all the places that Epic has custom integrations with other systems, with your insurer, etc, in that $500/patient, which is probably low, but gotta start somewhere). Add in the cost of re-training staff to use the new EMR, finding out after implementation the 'shadow IT' systems like someone exporting data to an excel spreadsheet and then doing a huge workflow on that that no one outside the department really knows about but is absolutely vital to the pharmacy's ability to operate...

OpenEHR can help address some things for one part of the system. But that is like saying fixing OpenSSL bugs will make all the internet secure.