There's actually a simple, low-tech, decentralized solution to this problem, for those of us who like such things. It's compatible with all providers, and even works across countries.

Step 1: Ask for, and obtain your medical records from your providers.

Step 2: Once you have your medical records in your possession, keep them organized, and share them with whoever you want, whenever you want.

I just keep them like one directory per doctor/provider, and dated filenames like dr-foo/2023-02-24-chest-xray.pdf or whatever.

Patients have an absolute right to their medical records, test results, with very few exceptions. It is _not_ hard to get access, just ask, and if you have any trouble, talk to whoever hands out and takes away the medical licenses in that jurisdiction.

If you have all your records, its easy to switch providers whenever you want, get second opinions, and do your own research. It can be pretty interesting seeing the raw notes from doctors, getting the DICOM files for x-rays/ct/mri imaging too.

Just keep, and take responsibility for your own data, it is not realistic to expect providers, the government, or any business to do this for you.

Are you familiar with Health information exchanges (HIE)?

This is a very challenging and important problem. I encourage to keep working on it.