In fact, I have a hard time editing in web browser textareas and Google Docs because of the muscle memory of vimlike keybindings and how I've associated them with tactile keyboards. (Smartphones and tablets don't give me this problem since they feel different, but laptop/desktop Google Docs editing throws me for a loop.)
Once you learn, modal is the way to go. It feels like playing a piano over an AST. It's so elegant for code and syntax trees.
I've been using vim keybindings in vim and vimlikes (JetBrains IDEs and VS Code) for nearly twenty years now. I learned most of it within just my first three months and have picked up additional surface area every year. I would still call myself a novice relative to vim masters, but you can get a ton of value from the basic movements and chords and occasional macros. All that to say, the learning curve might look steep, but it's shallower than you think and certainly well worth it.
The only reason I'd see non-modal being useful in a modal editor is as a crunch to learn and make the onboarding smoother. But you'd probably still want the first steps to be modal anyway, so I'm not sure it would provide much value.
Just jump in. It feels weird and slow at first, but let it grow on you. It pays dividends.
