Various HDD full data backups maintained with FreeFileSync, important files backup on ProtonDrive. Multi-device autosync with Syncthing (phones, tablet, pcs)

There’s plenty of software designed to store personal wikis and info in markdown, if you are interested checkout Obsidian, Logseq and Jopling (in that order for me)

One thing that is designed to be future-proof is MarkDown, I’ve been taking profesional and personal notes and exporting important information from web pages to markdown and hosting it on my own PC for a while.

MarkDown it’s text based so you can have a huge amount of data with just a tiny bit of space. And it is easily translated/rendered as HTML. Apps like Logseq, Obsidian or Markor are good starts for managing huge vaults of information.

I’m thinking that whe should create a MarkDown community here.

edit: There’s one already! https://lemmy.ml/c/pkb