The same here. I need more hand stability and it comes through practice. There are options to reduce the vibration and zigzag movement in most tools. I prefer I do the real way, not using stabilisers.
Free hand illustrations as much as I would love to be better at them, I have always found I struggle with them due to health issues I have that cause me to shake a little.
I do know of people who love to use free hand illustrations and some of their work has been amazing to see.