Same for me with Markdown. Love the simplicity.
I went through a phase a while back of evaluating a bunch of note-taking and to-do apps, and hating almost all of them for being proprietary products with so much vendor lock-in.
I eventually settled on Joplin because it just uses plain old markdown, and allows you to selfhost the storage back-end so you own your data.
So because of that, my recipes are just a folder (and some subfolders) with markdown in Joplin.



There’s nowhere convenient. As you correctly identified, AI has pushed the price of drives through the roof.
Your only real chance is to find a one-off on auction sites from someone who hasn’t noticed what’s going on or what the current market is asking for drives.
You might still be able to find bargains in charity stuff or on Marketplace sites etc but these are unlikely to be sufficient capacity for NAS builds unless you get super lucky.