Having been burned, many, many times, trying apps and formats that all were abandoned, I eventually realized that the only thing that would definitely last, over the long term, was a simple text file. The simpler the better. Simple is the only guarantee that something will last. Unix text files have not changed much since 1970s, it is the only thing in the tech world that has demonstrated longevity.
So I stick with a simple text file, and I will do so till the day I die.
While it's possible to somehow get my data back, it would be in a weird format or just a hassle to retrieve. I now use text files for everything (and mostly keep everything in emacs/org-mode).