There exists quantum-proof crypto algorithms.
The main issue with quantum cryptography (and cryptography in general) is that mathematical models are purely theoretical -- and not practically-minded. While yes, brute-forcing a decryption key for a quantum encryption is fucking madenningly retarded, the majority of cryptographic exploitation is done with other, more sane methods.
For instance,
- Side-Channel: Your encryption is only as secure as the machine that encrypts it. Exploiting (such as monitoring certain systems like the CPU cache) the parent system is a much simpler, easier, and more practically available method than brute-force. CPU cache, and other monitoring systems, are more "state actor" type shit, but simply having a compromised system (root/admin access by someone else) will make the private key completely available to anyone that has that access.
- Pre-Computed Rainbow Tables: Compute all decryption keys once, and reuse forever. Simple, quick, efficient, but for quantum yes it's not that practical.
- Backdoors: NSA/etc. intentionally sabotaging random number generators that narrow down the search space. Worse, if the software unintentionally implements a bad/broken cryptographic process (you're fucked)
Just a few, but there's much more. Elliptic curves (one "quantum" crypto) are the bees fucking knees though, and they should be used everywhere where maximum performance is not a concern.
In other words, use a strong crypto, but it's not your main concern. Making sure your software and hardware are on point is the real issue (because they're fuck all easily compromisable).
More on-topic: I use KeepassXC. It works on every system I use (Windows, OpenBSD, Linux, and yes even Android). GUI is really user-friendly with a lot of customizable database options. Exporting/importing is easy as hell -- it's just a kdbx file. So I can store it on my phone or even some cloud platform and be gucci.
I use it for all my important shit. Great for identity-management too, and it has notes so you can keep everything centralized. Hell, I even have all my personal documents (SSN, ID images, etc.) stored in that shit just in-case.