I’m looking for a veracrypt/truecrypt equivalent but at the folder-level and dynamic sizing
Something like a tool which could encrypt folders in real-time and then be able to lock it up. Truecrypt expects me to provide a size for it, I’d like something more dynamically sizeable based on the files I store in it.
Even just a tool that encrypts files written into it and converts them to other files works with me
CryFS does what you want, it’s the default used by the KDE Vaults feature.
there’s also a comparison page on the site, comparing it to other solutions.