Just an update: I mostly regret trying to get the car back on it's feet. The main problem is the CVT, that's what causes the shuddering, not the coil packs.

I replaced the coil packs, engine oil, coolant, changed the oil filter, changed the air filter & cabin filter, ran some engine/injection cleaner through the fuel.

The occasional hiccup went away. The shuddering on acceleration was unchanged. It actually got noticeably worse over time. I paid a place to do the CVT fluid flush/change which had a little impact and combined with this calibration tip had a fair bit more impact but it's still very noticeable even when starting slowly on a flat surface and ridiculous when starting on any kind of upward slope.

All up I've spent over $1k and things have only gotten a bit better. The car is still not really saleable, I don't think, and never will be because of that starting shudder.