mini.surround: how to assume motions if none are specified?

[Oneechan69]

for instance, I want to write sa" in normal mode (no motions) and have it assume iw (like saiw") or whatever I write in a config option for a default motion.

[echasnovski]

I am afraid, this is not how operators (and sa is a regular operator) in Neovim work. They always assume that next typed characters define textobject or motion to act upon. So in this case Neovim will treat " as textobject/motion and stop early because it (presumably) doesn't know textobject/motion with that start with that character.

The best you can do is to create custom Normal mode mappings for some common surroundings individually. So something like this:

-- **Do not** forget the `remap = true` part, it makes it treat keys "as if typed by user"
vim.keymap.set('n', 'sa"', 'saiw"', { remap = true })