In the end I've just been using the Unix pass password manager [1].
It's just cobbling together of GPG and git with shell scripts but it works like a normal git repository so you get all your synchronization, from that, your security from GPG which are all things I know and trust without introducing other components that I don't know / understand.
For developers/tech-savvy people it is more or less perfect. I love the fact that it is based on git giving you a history and great control over synchronization. I use it to store all kinds of things such as passwords and files containing environment variables that can be sourced directly from the output of pass (source <(pass dotenv/project)). It even exists a great open-source iOS client: https://github.com/mssun/passforios