If you've ever used Ctrl+C to copy, you've already done something harder than the core concept of modal editing. Modal editing is simpler: you press a single key, and you switch to one (of two) modes. That's it. That's the thing people find intimidating. In one mode the letters you press show up on the screen, in the other the letters you press select/copy/move/etc (like cntrl+c... Except even simpler you only need to press one key). You have to use keyboard keys to go up and down, which I assume you already have some experience with.

Learning it is identical to learning a GUI. In Word, you hunt through menus for the word 'cut' or 'paste' and click it. In a modal editor like helix you look up cut or paste on a menu and press the key next to it instead. Except once you remember the key you never have to go look through menus again!

Get the hang of it and modal text editors are to word processors what word processors are to typewriters. Except at least typewriters have some charm.

All that being said, if you want to sync your notes you'll have to use something like Dropbox or google drive, and I looked up how to install helix and you do have to download and unzip a file (https://github.com/helix-editor/helix/releases). Still, computer science degree not required!

Unless you've only ever used android or iOS device in which case all of my assumptions about your familiarity with keyboards and mice is totally off. Still!